Optical-fiber-spliced portion reinforcing heating device

ABSTRACT

An optical-fiber-spliced portion reinforcing heating device of the invention includes: a pair of clamps that respectively grasp a coated portion of an optical fiber, the optical fiber including a fusion-spliced portion, the fusion-spliced portion being coated with a sleeve, the coated portion being exposed from the sleeve; at least two or more heaters that are arranged to face each other so as to sandwich the sleeve; a first force-applying member that presses at least one of the paired clamps so as to apply a tension to the optical fiber; and a second force-applying member that applies a pressing force to at least one or more of the heaters via the sleeve by use of one of an elastic member and a magnetic member in accordance with control of a drive source, the heaters being arranged to face each other with the sleeve interposed therebetween.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a divisional application of U.S. Ser. No. 14/600,731 filed Jan.20, 2015, which is a Continuation of PCT Patent Application No.PCT/JP2014/058371, filed Mar. 25, 2014, whose priority is claimed onJapanese Patent Application No. 2013-063014 filed on Mar. 25, 2013, thecontents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates to an optical-fiber-spliced portionreinforcing heating device.

DESCRIPTION OF THE RELATED ART

Generally, when optical fibers are fusion-spliced, the following worksequence is carried out.

(1) An optical fiber is extracted from an optical fiber cable.(2) A resin coating (front end) that coats the extracted optical fiberis removed by a removing tool of an optical fiber coating.(3) After the coating is removed from the front end, scraps of the resincoating remain on a surface of a glass (bare optical fiber) of theoptical fiber, and the scraps are removed by a cloth or a papermoistened with alcohol.(4) The clean optical fiber is cut by an optical fiber cutter.(5) The cut optical fibers are fusion-spliced by an optical fiber fusionsplicer.(6) The post-fusion-spliced optical fiber is covered with aheat-shrinkable reinforcement sleeve and is heat-reinforced by a heaterof a fusion splicer.(7) The heat-reinforced optical fiber is accommodated in a storage trayof a spliced portion storage case.

In the above-described step (6), the outer side of the sleeve used toreinforce the optical fiber spliced portion is formed of a heatshrinkable tube, a hot melt disposed inside thereof is molded at thecircumference of the optical fiber, and the spliced portion is therebyprotected.

The sleeve formed by the outer heat shrinkable tube and the inner hotmelt is heat-shrinkable depending on various coating diameters of theoptical fiber.

Additionally, as a result of heat-shrinking the sleeve at substantiallythe center in the longitudinal direction thereof at first, the sleeve ismolded while extruding air inside the sleeve from the sleeve center tothe outside thereof.

The optical fiber spliced portion that is reinforced by theabove-described sleeve also has a function of blocking an externalsubstance such as moisture which adversely affects an optical fiber.

Between the outer heat shrinkable tube and the inner hot melt, astainless-steel tensile strength member is inserted into the sleeve inadvance in the case of a single-core optical fiber and a glass tensilestrength member is inserted into the sleeve in advance in the case of amulti-core ribbon, and a structure that resists bending or tension isthereby realized.

Moreover, shrinking can be carried out at high speed such asapproximately 30 seconds by use of an optical-fiber-spliced portionreinforcing heating device which is conventionally mounted on an opticalfiber fusion splicer.

In order to heat-shrink a sleeve, in recent years, polyimide filmheaters are used which are adhesively attached to a metal sheet andserve as a heater provided on an optical-fiber-spliced portionreinforcing heating device (hereinbelow, may be referred to as areinforcing heating device); and a heater is proposed as an examplehaving single flat sheet heater into which two or more heaters circuitpatterns are implanted (for example, refer to Japanese Patent No.3293594, hereinafter referred to as Patent Document 1 and refer toJapanese Unexamined Patent Application, First Publication No.2010-249887, hereinafter referred to as Patent Document 2).

As mentioned above, generally, a plurality of heater circuit patternsare implanted into a flat sheet heater.

Furthermore, a technique of working and heating a flat sheet heater in aU-shape is also proposed (for example, refer to Japanese Patent No.4165375, hereinafter referred to as Patent Document 3).

Furthermore, generally, in order to prevent a sleeve from beingpositionally displaced from an optical fiber spliced portion whentension is applied to an optical fiber from the outside before heatshrinking of the sleeve, a clamp is provided at a reinforcing heatingdevice.

As such clamp, a clamp provided with a tension applying mechanism isknown, and by using this, an optical fiber is prevented from going slackin the sleeve.

If the sleeve shrinks in a state in which the optical fiber has a slack,stress remains in the optical fiber inside the sleeve, there is aconcern that the long-term reliability of the optical fiber is degraded;particularly, in the reinforcing heating device that reinforces a ribbonby heating, the clamp is an essential and necessary configuration toprevent arrayed bare optical fibers from coming in contact with eachother.

If tension is not applied to the fiber, the optical fibers adjacent toeach other shrink in a state of being in contact with each other,damaging both optical fibers, and therefore, the long-term reliabilityof the optical fiber is decreased.

In order to solve the aforementioned problems, a reinforcing heatingdevice used for multi-core tape fibers is proposed, in which clamps arearranged at both sides of the heater in the longitudinal direction ofthe optical fiber, one of the clamps is configured to slidably move inthe longitudinal direction of the optical fiber, and a compression coilspring is provided (for example, refer to Japanese Unexamined PatentApplication, First Publication No. 2000-321462, hereinafter referred toas Patent Document 4).

In a constitution of Patent Document 4, a tension is applied to anoptical fiber by use of a clamp in the sequence described below.

In a first method, an optical fiber is set in a state in which right andleft clamps are opened, the movable left clamp is only closed,subsequently, the optical fiber is pulled in the right direction, andthe right clamp is closed in a state in which a compression coil springis contracted.

At this time, the shrinkage of the compression coil spring is designedto generate optimal tension in the optical fiber at the position atwhich the movable left clamp is brought into contact with the right endof the movable range, and the optimal tension of the compression coilspring is always applied to the optical fiber.

Additionally, in a second method, the left side face of a movable clampis pressed in the right direction with the finger in a state in whichright and left clamps are opened, shrinkage of a compression coil springis designed to cause an optical fiber to generate an optimal tension atthe position with which the left clamp is brought into contact in theright direction.

Thereafter, the optical fiber is set to the clamp in a state of beingpressed with the finger, the movable left clamp and the fixed rightclamp are closed.

Subsequently, by removing the finger from the movable left clamp, anoptimal tension due to the compression coil spring is always applied tothe optical fiber.

However, the method disclosed in the above-mentioned Patent Document 4,in a state after the optical fiber is set to the clamp without slack bypulling it with the finger and the right and left clamps are closed, aforward movable range that allows the movable left clamp to further movetoward the heater side does not remain almost, and a backward movablerange is only ensured in this state.

In above-described state, in the case of applying an excessive lateralpressure to the optical fiber, there is a problem in that a residualtensile force that causes the long-term reliability of the optical fiberto be significantly deteriorated is applied to the optical fiber or theoptical fiber is immediately broken.

Furthermore, instead of the aforementioned compression coil spring,application of a tension to an optical fiber by utilizing a magneticforce is proposed (refer to, for example, Japanese Patent No. 3337874,hereinafter referred to as Patent Document 5).

In FIG. 1 or the like shown in Patent Document 5, a right clamp ismovable and a left clamp is fixed.

The movable clamp is generally pressed onto a heater side by a tensioncoil spring.

Subsequently, when the optical fiber is grasped (clamped) and the lid ofthe heater is closed, a repulsion force is generated between magnets,and a tension is applied to the optical fiber.

Because of this, complicated steps such as two methods disclosed inPatent Document 4 are not necessary, and the tension is automaticallyapplied to the optical fiber by only closing the clamp or the lid.

However, in the technique disclosed in Patent Document 5, similarly, theoptical fiber is set to the clamp without slack by pulling it with thefinger, a movable range that allows the movable clamp to further movetoward the heater side hardly remains in a state after the right andleft clamps are closed, and a backward movable range is only ensured inthis state.

In above-described state, in the case of applying an excessive lateralpressure to the optical fiber, there is a problem in that a residualtensile force that causes the long-term reliability of the optical fiberto be significantly deteriorated is applied to the optical fiber or theoptical fiber is immediately broken.

In addition, generally, for a reinforcing heating device used for asingle-core optical fiber, a device that is provided with a mechanismapplying tension does not almost exist.

The reason is that, adjacent optical fibers are in contact with eachother in the case of a single-core optical fiber, and therefore, in mostcases, in order to reduce the cost of the device, it is not providedtherefor.

That is, such mechanism applying tension to an optical fiber is mainlymounted on a reinforcing heating device used for a multi-core opticalfiber.

Here, in the case of shrinking the sleeve in a state in which a tensionis applied to the optical fiber, a residual tension remains in theoptical fiber.

In the case of a normally-used optical fiber having the surface which isnot damaged, a long-term reliability is not degraded under a residualtension of 100 gf or less. Conventionally, it is recommended for theresidual tension of an optical fiber to be less than or equal to 100 gf(for example, refer to Japanese Unexamined Patent Application, FirstPublication No. H10-332979, hereinafter referred to as Patent Document6).

However, a fusion-spliced optical fiber may be damaged due to the workoperation therefor. Therefore, in the case where, for example, a tensionis 200 gf under a rupture evaluation test after the optical fibers arespliced, it is recommended to be less than or equal to 30 gf.

Generally, in the case of splicing optical fibers, the amount of time offusion-splicing is less than or equal to 10 seconds; however, an amountof time of 25 seconds or more is required for heat shrinking.

For example, it is believe to take 40 seconds to connect an opticalfiber to a reinforcing heating device or to remove the optical fibertherefrom.

Generally, dozens of optical fibers are provided in one optical fibercable, so, it takes approximately 1 hour to splice together ninety-sixoptical fibers (96 fibers×40 seconds=3840 seconds 1 hour). Thus, ittakes 1 hour only to carry out an operation of heat-reinforcing sleevein order to splice one cable, and shortening of heat shrinking time isimportant.

Generally, in a device which heat-reinforce an optical fiber splicedportion, as a result of pressing a sleeve onto a heater and therebydeforming the sleeve, it is possible to shorten the heating time byheating the sleeve in a state in which the area of contact between theheater and the sleeve increases and the heat is easily transmitted.

Hitherto, a plurality of techniques of shortening the heating time as aresult of positively causing the heater to come into contact with thesleeve are proposed.

Here, in the aforementioned Patent Document 6, a method of pressing aheater onto a sleeve by use of a compression coil spring and of alwaysmaintaining the contact state is described.

In Patent Document 6, a mechanism is provided which absorbs a tension byuse of a compression coil spring when the tension is applied to anoptical fiber by pressing by a heater.

Moreover, in this constitution, as a result of providing the left slideclamp and the compression coil spring, a tension is applied to anoptical fiber so as to prevent occurrence of a slack thereof in a mannersimilar to a conventional heating device.

However, in the left slide clamp of Patent Document 6, the backwardmovable range explained above is ensured; however, a forward movablerange is not provided.

In the case where an allowable residual tension of an optical fiber is10 to 100 gf, the total pressing force due to a heater is required to beless than or equal to 10 to 100 gf.

In the case where, for example, a tension is 200 gf under a ruptureevaluation test after the optical fibers are spliced, the allowabletension is less than or equal to approximately 30 gf, and the pressingforce due to a heater is required to be less than or equal to 30 gf.

As will be described later, there is a problem in that the sleeve cannotbe sufficiently deformed in 30 gf.

Even if, a pressing force of several hundreds of gf is applied to theheater at the side surface thereof, a compression coil spring thatapplies a tension of 30 gf thereto is unconscionably and quickly shrunk,a forcible tension of several hundreds of gf is applied to the opticalfiber, and there is a problem in that the long-term reliability of theoptical fiber after reinforcement is degraded.

As a result, in Patent Document 6, it is not possible to increase thepressing force of the heater to be greater than the allowable residualtension of the optical fiber.

Here, a method of always maintaining the contact between the heater andthe sleeve by causing a hard core provided in the sleeve to be in closecontact with a magnet is proposed (for example, refer to JapaneseUnexamined Patent Application, First Publication No. 2010-217271,hereinafter referred to as Patent Document 7).

However, in the method of Patent Document 7, the hard core inside thesleeve and the heater are attracted to each other due to the magnet;however, there is a problem in that, in the sleeve structure, a pressingforce to deform the entire sleeve by squashing cannot be appliedthereto.

For this reason, the contact between the heater and the sleeve can bemaintained; however, the effect of increasing the contact area thereofcan hardly be obtained.

Furthermore, in the case where the hard core is made of glass, it doesnot function.

Additionally, in the case of using a permanent magnet, since the magnetis disposed near the heater, there is a problem of degradation inmagnetic force which is due to a high temperature.

In other case, a constitution is proposed which serves as a device ofheat-reinforcing an optical fiber spliced portion, includes: a means ofdriving a heater by use of using a motor or the like; and a means ofdetecting that the heater moves forward to a predetermined position,i.e., a position where the sleeve is shrunk, and is configured toretreat after the heater moves forward to the sleeve position and theheater reaches a predetermined position (for example, refer to JapaneseUnexamined Patent Application, First Publication No. 2004-042317,hereinafter referred to as Patent Document 8).

According to Patent Document 8, two heaters press the sleeve, the areaof contact between the sleeve and the heater increases, and it ispossible to speed up the heat shrinking of the sleeve.

Particularly, the heat conduction efficiency due to the heater becomeshigher, it is possible to shorten the heat shrinking time of the sleeve.

According to this system, it is possible to sufficiently deform thesleeve.

The inventor intensively researched how degree of the pressing force isapplied to the sleeve so as to be deformed in order to shorten the heatshrinking time to be shortest; it is apparent that the pressing force of500 gf to press the sleeve by the heater is required when the sleeve isheat-shrunk.

As shown in the chart of FIG. 30, as the pressing force of the sleevebecomes higher, the contact area between the heater and the sleeveincreases, and the shrinking time of the sleeve becomes short.

FIG. 30 is a chart showing a case where a commonly-used sleeve of 60 mmwhich is used for single core is sandwiched between two heaters andheating is carried out at a temperature of 230° C. of both two heaterswhere one of the heaters is fixed and the other of the heaters ismovable.

It is understood from this chart that, when the pressing force exceeds500 gf, the pressing effect decreases, the shrinking time of the sleeveis not much shorter.

In addition, the aforementioned changing point of approximately 500 gfvaries with the sleeve structure. Particularly, in the case of acommonly-used sleeve of 60 mm which is used for single core, thevariation in the shrinking time reduces when the pressing force exceedsapproximately 500 gf.

However, in the technique disclosed in Patent Document 8, there isproblems described below.

Firstly, there is a first problem due to pressure of the sleeve bymovement control of a heater.

The heater moves forward by a motor through a micrometer, it isnecessary for the amount of the forward movement and the forwardvelocity thereof to control depending on a state in which a sleeve iscontracted.

However, various kinds of sleeve are used, the amount of forwardmovement and the forward velocity vary depending on, for example,difference in the diameter or the material thereof.

Furthermore, a contractile rate of the sleeve varies depending on anoutdoor temperature or a voltage of a built-in battery.

In addition, in the longitudinal direction of the sleeve, generally, thecontractile rate of the center portion thereof is different from that ofthe outer-edge portion thereof.

Consequently, in the case where the heater excessively moves forward, anexcessive pressure reaches the optical fiber provided thereinside, andthe optical fiber is thereby damaged.

Alternatively, if the forward movement of the heater is delayed, a gapoccurs between the heater and the sleeve, there is also a problem inthat the sleeve is not shrunk in a shorter amount of time.

In order to make the pressing force of the heater constant, it isnecessary to press the heater onto the sleeve by use of an elasticmember. In the disclosure of Patent Document 8, a heater is pressed ontoa sleeve by use of an elastic member and a cam.

More specifically, Patent Document 8 also discloses the constitution inwhich the cam is disposed between right-and-left arranged heaters, eachheater is pressed by the elastic member such as a spring, and the heateris pressed onto a heat shrinkable sleeve by rotating the cam using amotor.

Hereinbelow, while pressing two heaters by spring as described above, asystem of driving the heater by the cam inserted therebetween will bedescribed with reference to FIG. 32 states (a) to (c).

FIG. 32 state (a) shows a state shortly after a sleeve 312 is setbetween two heaters 321 and 322 and before heating is started.

In the drawing, an optical fiber 311 provided inside the sleeve 312 islocated on the center line S indicated by a dashed-dotted line.

Moreover, the position of the optical fiber 311 is held and fixed byclamps which are positioned in front of and at the rear side of theheaters 321 and 322 and not shown in the figure.

Subsequently, as shown in FIG. 32 state (b), a cam 323 rotates, the twoheaters 321 and 322 are pressed onto the sleeve 312 by forces ofcompression coil springs 324 and 325, and heating of the heaters 321 and322 is thereby started.

In the drawing, the cam 323 does not come into contact with movabletables 321A and 322A, and the sleeve 312 is pressed by the forces of thecompression coil springs 324 and 325.

At this time, as long as the position of the optical fiber 311 islocated on the center line S indicated by a dashed-dotted line, anexcessive tension is not applied to the optical fiber 311.

Next, as it is in this state, the sleeve 312 shrinks, thereafter beingcompletely shrunk, and heating reinforcement is completed. In thissituation, if the position of the optical fiber 311 does not displacefrom the center line S as described above, an excessive tension is notapplied to the optical fiber 311.

However, as a practical matter, the pressing forces of theright-and-left arranged compression coil springs 324 and 325 in thedrawing are not the same as each other, the sleeve 312 does not stay onthe center line S, and it is difficult for the two compression coilsprings 324 and 325 to be always located at the same position whilebeing continuously balanced for a long period of time.

For example, as shown in FIG. 32 state (c), in a general state, thecompression coil springs 324 and 325 are located near the side of anyone thereof due to a difference in force between the compression coilsprings.

In the state shown in FIG. 32 state (c), the movable table 321A that isdisposed at the left side in the drawing is brought into butt-contactwith the left-side housing and stopped.

For this reason, in FIG. 32 state (c), the position of the optical fiber311 is displaced from the center line S; furthermore, since the opticalfiber 311 is fixed by the clamp which is not shown in the figure, if theabove-mentioned slight displacement occurs, the excessive tensions ofthe compression coil springs 324 and 325 are applied to the opticalfiber 311.

In the technique disclosed in Patent Document 8, there is a secondproblem in that an excessive pressing force is applied to the opticalfiber.

The force of approximately 500 gf by which the sleeve is pressed isextremely larger than the tension of approximately 30 gf which can beapplied to the above-described post-fusion-spliced optical fiber, thisforce is two or more times the tension of 200 gf under the ruptureevaluation test, and therefore, there is a concern that the opticalfiber is broken at the moment at which the pressing force is appliedthereto.

Even if breaking does not occur, the long-term reliability of theoptical fiber is degraded.

In the technique disclosed in Patent Document 8, there is a thirdproblem in that a mechanism that applies a tension to the optical fiberis necessary.

In the method of pressing both sides of the sleeve 312 as describedabove, before performing the pressing by the heaters 321 and 322, it isnecessary for the sleeve 312 to be in the state of being suspended fromthe optical fiber 311 to which a tension is applied in advance.

However, as shown in FIG. 33 views (a) and (b), in a case where theclamps 326 and 327 grasps the optical fiber 311 in a state in which atension is not applied to the optical fiber, slack of the optical fiber311 occurs immediately after clamping, and the position of the sleeve312 is displaced downward.

In the foregoing case, as shown in FIG. 33 views (a) and (b), the sleeve312 is not pressed at a proper position by the heaters 321 and 322,there is a concern that the work operation therefor is completed in astate in which shrinkage is not completed.

As a countermeasure against this case, it is thought that the heaters321 and 322 are configured to be longer in the vertical directionthereof in consideration of the case where the position of the sleeve312 is displaced downward; however, as the heaters 321 and 322 arelarger in size, the heat capacity thereof increases, and there is aproblem in that the rate of temperature increase decreases.

As a method of removing such slack of the above-mentioned optical fiber,it is required that a fixed tension is applied to a clamp grasping theoptical fiber by use of, for example, an elastic member such as a springor a magnetic member such as a magnet.

That is, in the two method described in the explanation of theabove-described Patent Document 4, the method of using a magnetic forcedescribed in Patent Document 5, the method of Patent Document 6, it isnecessary to apply a tension to the optical fiber.

In the technique disclosed in Patent Document 8, there is a fourthproblem due to the size of the device.

By using a micrometer or a screw mechanism as a system of driving theheater, it is possible to provide a pressing force exceeding 500 gf.

However, since a fusion splicer that splices optical fibers is used onabove a telegraph pole or in a narrow space such as a narrow manhole andsince it is necessary to splice optical fibers having even a shorterexcess length, a reduction in device size is required.

Because of this, in the case where two motors and two micrometers or twoscrew mechanisms are provided inside such fusion splicer, the devicesize increases, and there is a problem in that it is not suitable to awork operation environment or it is possible to splice optical fibershaving a shorter excess length.

As a result, a fusion splicer provided with a drive mechanism obtainingthe above-mentioned pressing force is not put to practical use.

Even in the case of using any technique described in the aforementionedPatent Documents 4, 5, and 6 in order to apply a tension to an opticalfiber, since the movable clamp cannot move forward to the direction ofthe heater after the optical fiber is clamped, as a result, the movableclamp cannot absorb this tension when a large tension is applied to theoptical fiber by the pressure of the heater.

Accordingly, it is not possible to remove the tension that isexcessively applied to the optical fiber, there is a problem causingbreaking of the optical fiber or degradation in long-term reliabilitythereof.

That is, in a conventional reinforcing heating device, due to theproblem of the long-term reliability of the optical fiber, the sleevecannot be pressed so as to be deformed.

By use of the technique described in the above-described Patent Document8, it is possible to realize that a sleeve is pressed by the forceexceeding a tension under a rupture evaluation test; however, a varietyof mechanism elements as well as a motor is necessary, as a result, thedevice becomes larger in size.

That is, in a conventional reinforcing heating device, due to alimitation in device size, the sleeve cannot be pressed so as to bedeformed.

SUMMARY OF THE INVENTION

The invention was made with respect to the above-described problems andhas an object to provide an optical-fiber-spliced portion reinforcingheating device which prevents an excessive tension from being applied toan optical fiber and thereby prevents the optical fiber from beingbroken or prevents the long-term reliability thereof from beingdegraded, which has a high level of handleability in addition toprevention of the device from being larger in size, and which canheat-shrink a sleeve in a short amount of time.

In order to solve the aforementioned problem, the invention provides anoptical-fiber-spliced portion reinforcing heating device characterizedto include: a pair of right and left clamps that respectively grasp oneportion of a coated portion of an optical fiber and the other portionthereof, the coated portion being exposed from a sleeve, where opticalfibers are fusion-spliced at which the coated portion is removed and acoating-removed portion of a fusion-spliced portion and the coatedportion of the optical fibers are covered with the sleeve; at least twoor more heaters that are arranged to face each other so as to sandwichthe optical fiber or the sleeve; a first force-applying member thatpresses at least one of the clamps so as to apply a tension to theoptical fiber by use of one of an elastic member and a magnetic member;and a second force-applying member that applies a pressing force to atleast one or more of the heaters via the sleeve by use of one of anelastic member and a magnetic member in accordance with control of adrive source, the heaters being arranged to face each other with thesleeve interposed therebetween, wherein a pressing force that is to beapplied to the sleeve by the second force-applying member is set to begreater than a tension that is to be applied to the optical fiber by thefirst force-applying member, and in a state in which a tension isapplied to the optical fiber by the first force-applying member, one ofthe clamps applying the tension is configured so that a backward movablerange in a direction away from the heaters in the longitudinal directionof the optical fiber is ensured, a forward movable range that allowsmovement to the heater side is ensured, and the clamp moves in adirection in which a tension that is applied to the optical fiber as aresult of pressing the sleeve by the heaters and by the secondforce-applying member is diminished.

In the aforementioned configuration, a configuration may also be adoptedin which one of the heaters that are arranged so as to face each otherwith the sleeve interposed therebetween is movable and the other thereofis fixed.

In the aforementioned configuration, a configuration may also be adoptedin which a pressing force that is to be applied to the sleeve by theheaters exceeds the tension of the fusion-spliced portion of the opticalfiber under a rupture evaluation test.

In the aforementioned configuration, a configuration may also be adoptedin which the heaters have pressing faces that face each other with thesleeve interposed therebetween are arranged in a substantially verticaldirection, a tensile strength member is consistently arranged in asubstantially downward direction by utilizing a weight of the tensilestrength member that is inserted into the inside of the sleeve, and thedirection of the sleeve is thereby constant.

In the aforementioned configuration, a configuration may also be adoptedin which after heating of the sleeve is completed, the heaters areimmediately separated from the sleeve, heat-transfer to the sleeve isinterrupted, and the sleeve is thereby rapidly cooled by introduction ofexternal air into the periphery of the sleeve.

In the aforementioned configuration, a configuration may also be adoptedin which, before the optical fiber is grasped, in a state in which oneof the clamps moves separately from the heaters by the firstforce-applying member and comes into contact with a backward movementstopper and a movable range is ensured only in a forward movementdirection, in a state in which the paired right and left clamps graspthe optical fiber and a tension is not applied to the optical fiber,immediately after the optical fiber is grasped, or at the time ofstarting of pressing drive with respect to the sleeve by the heaters, orbefore or after the time of the starting of the pressing drive, thebackward movement stopper is retracted, in a state in which the tensionis applied to the optical fiber, the forward movable range of one of theclamps is ensured in addition to the backward movable range, andthereafter the heaters press the sleeve.

In the aforementioned configuration, a configuration may also be adoptedin which, before the optical fiber is grasped, from a state in which oneof the clamps is separated from the heaters by the first force-applyingmember and is in contact with a backward movement stopper to a state inwhich the clamp moves forward until coming into contact with a forwardmovement stopper and is maintained, in a state in which the paired rightand left clamps grasp the optical fiber and a tension is not applied tothe optical fiber, immediately after the optical fiber is grasped, or atthe time of starting of pressing drive with respect to the sleeve by theheaters, or before or after the time of the starting of the pressingdrive, one of the clamps is released from the contacting state withrespect to the forward movement stopper and the forward movement stopperis retracted, in a state in which the tension is applied to the opticalfiber, a forward movable range is ensured in addition to a backwardmovable range of one of the clamps, and thereafter, the heaters pressthe sleeve.

In the aforementioned configuration, a configuration may also be adoptedin which, before the optical fiber is grasped, in a state in which anapplied force in a backward movement direction away from the heaters isapplied to one of the clamps by the first force-applying member and in astate in which one of the clamps is stopped at a position away from anend of a movable range thereof by a third force-applying member formedof an elastic member or a magnetic member which is used to move one ofthe clamps in a forward movement direction, in a state in which thepaired right and left clamps grasp the optical fiber and a tension isnot applied to the optical fiber, immediately after the optical fiber isgrasped, or at the time of starting of pressing drive with respect tothe sleeve by the heaters, or before or after the time of the startingof the pressing drive, in a state in which the paired right and leftclamps apply a tension to the optical fiber as a result of decreasing anapplied force of one of the clamps in the forward movement direction bythe third force-applying member, as a result of increasing an appliedforce in the backward movement direction by the first force-applyingmember, or as a result of retracting the third force-applying member, aforward movable range is ensured in addition to a backward movable rangeof one of the clamps, and thereafter, the heaters press the sleeve.

In the aforementioned configuration, a configuration may also be adoptedin which both the paired right and left clamps are movable back andforth in the longitudinal direction of the optical fiber, before theoptical fiber is grasped, in a state in which one of the clamps isseparated from the heaters by the first force-applying member and is incontact with a backward movement stopper and a movable range is ensuredonly in the forward movement direction and in a state in which the otherof clamps moves forward to the heater side and is stopped before theoptical fiber is grasped, in a state in which the paired right and leftclamps grasp the optical fiber and a tension is not applied to theoptical fiber, the other of clamps starts to move in a backward movementdirection away from the heater side, one of the clamps moves in aforward movement direction which is due to a tension transmitted throughthe optical fiber, movement of the other of clamps is stopped at aposition away from an end of a movable range of one of the clamps,therefore, in a state in which the tension is applied to the opticalfiber, a forward movable range is ensured in addition to a backwardmovable range of one of the clamps, and thereafter, the heaters pressthe sleeve.

In the aforementioned configuration, a configuration may also be adoptedin which, before the optical fiber is grasped, in a state in which oneof the clamps is separated from heaters by the first force-applyingmember and is in contact with a backward movement stopper and a movablerange is ensured only in the forward movement direction and in a statein which the paired right and left clamps grasp the optical fiber and atension is not applied to the optical fiber, the heaters press thesleeve by a pressing force by the second force-applying member which isgreater than a tension that is to be applied to the optical fiber by thefirst force-applying member, as a result of moving the optical fiber ina pressing direction which is due to movement of the sleeve ordeformation of the sleeve after starting of the press, one of the clampsis drawn to a forward movement direction by a tension due to movement ofthe optical fiber, one of the clamps is configured so as to be stoppedat a position away from an end of a movable range, therefore, in a statein which a tension is applied to the optical fiber by the firstforce-applying member, a forward movable range is ensured in addition toa backward movable range of one of the clamps, and thereafter, theheaters heat the sleeve.

Additionally, the invention provides an optical-fiber-spliced portionreinforcing heating device characterized to include: a pair of right andleft clamps that respectively grasp one portion of a coated portion ofan optical fiber and the other portion thereof, the coated portion beingexposed from a sleeve, where optical fibers are fusion-spliced at whichthe coated portion is removed and a coating-removed portion of afusion-spliced portion of the optical fibers is covered with the sleeve;a fifth force-applying member that is provided on at least one of theclamps that are arranged to face each other with the optical fiberinterposed therebetween, sandwiches the optical fiber by use of one ofan elastic member and a magnetic member, and applies a pressing forcethereto; a first cam mechanism that is driven to rotate by controlling amotor; a mechanism that controls to grasp the optical fiber by theclamps and by the pressing force of the fifth force-applying member dueto displacement of the first cam mechanism; at least two or more heatersthat are arranged to face each other so as to sandwich the optical fiberor the sleeve; a second force-applying member that applies a pressingforce to at least one or more of the heaters via the sleeve by use ofone of an elastic member and a magnetic member, the heaters beingarranged to face each other with the sleeve interposed therebetween; athird cam mechanism that is disposed on the camshaft on which the firstcam mechanism is provided or is disposed on the other camshaft parallelto the camshaft, and is driven to rotate by controlling the motor; and amechanism that controls to press the sleeve by the heaters and by thepressing force of the second force-applying member due to displacementof the third cam mechanism; wherein the same motor controls the clampsand the heaters by the force of each of the force-applying members andby the first and third cam mechanisms.

In the aforementioned configuration, a configuration may also be adoptedin which, in two or more cam mechanisms used in the first cam mechanismand the third cam mechanism which are rotationally driven by the samemotor, a rotating drive force by the drive source is reduced bydetermining a timing of combining a positive driving that needs a rotarydrive torque and a negative driving that receives a torque to bediminished.

In the aforementioned configuration, a configuration may also be adoptedin which, in at least one of two or more cam mechanisms used in thefirst cam mechanism and the third cam mechanism, an auxiliary movablemember is disposed on the opposite side of each operation member withthe camshaft interposed therebetween, each operation member is coupledto the auxiliary movable member by use of one of an elastic member and amagnetic member, a rotary drive torque of each cam mechanism is reversedfrom positive driving to negative driving as a result of displacing theauxiliary movable member instead of the operation member in accordancewith a motion of each cam mechanism, and the positive driving and thenegative driving are thereby combined and diminished in the two or morecam mechanisms.

In the aforementioned configuration, a configuration may also be adoptedin which, regarding the paired right and left clamps and the heaters,one of them is movable, and the other of them is fixed.

In the aforementioned configuration, a configuration may also be adoptedwhich includes: a first force-applying member that presses at least oneof the clamps so as to apply a tension to the optical fiber by use ofone of an elastic member and a magnetic member; a second cam mechanismthat is disposed on the camshaft that is the same camshaft as those ofthe first cam mechanism and the third cam mechanism or is disposed onthe other camshaft parallel to the camshaft, and is driven to rotate bycontrolling a motor; and a mechanism in which displacement of the secondcam mechanism controls a tension of the optical fiber which is due to atension of the first force-applying member of the clamps, wherein thesame motor controls the clamps, the tension mechanism, and the heatersby a force of each of the force-applying members and by the first tothird cam mechanisms.

In the aforementioned configuration, a configuration may also be adoptedwhich further includes: a position limiting member that is configured ofa forward movement stopper or a backward movement stopper, which limitsa forward movable range or a backward movable range of at least one ofthe paired right and left clamps; a fifth cam mechanism that is to berotationally driven by the motor control, the cam mechanism beingdisposed on the same camshaft as those of the first to third cammechanisms or disposed on the other camshaft parallel to the camshaft;and a mechanism in which displacement of the fifth cam mechanismcontrols movement of the position limiting member, wherein the samemotor controls the clamps, the tension mechanism, the heaters, and theposition limiting member by the first to third and fifth cam mechanisms.

In the aforementioned configuration, a configuration may also be adoptedwhich further includes: the first force-applying member that limits aforward movable range or a backward movable range of at least one of thepaired right and left clamps or the third force-applying member thatapplies a tension in an opposite direction relative to the firstforce-applying member; a sixth cam mechanism that is disposed on thesame camshaft as those of the first to third cam mechanisms or disposedon the other camshaft parallel to the camshaft and that is to berotationally driven by the motor control; and a mechanism in whichdisplacement of the sixth cam mechanism controls an applied force of thefirst force-applying member or the third force-applying member to bestronger or to be weaker, wherein the same motor controls the clamps,the tension mechanism, the heaters, and the first or the thirdforce-applying members by the first to third and the sixth cammechanisms.

In the aforementioned configuration, a configuration may also be adoptedwhich includes: a lid that opens and closes the optical-fiber-splicedportion reinforcing heating device; a sixth force-applying member thatapplies a force of closing the lid thereto by use of one of an elasticmember and a magnetic member; a fourth cam mechanism that is disposed onthe same camshaft as those of the first to third cam mechanisms ordisposed on the other camshaft parallel to the camshaft; and a mechanismin which displacement of the fourth cam mechanism controls opening orclosing of the lid by an applied force of the sixth force-applyingmember, wherein the same motor controls the clamps, the tensionmechanism, the heaters, and the lid by the force-applying members and bythe first to fourth and sixth cam mechanisms.

In the aforementioned configuration, a configuration may also be adoptedin which at least any of the clamps, the tension mechanism, the heaters,and the lid is configured by a lever-shaped member that rotationallymoves around a rotation support parallel to the optical fiber and thesleeve or is provided at a lever-shaped member.

In the aforementioned configuration, a configuration may also be adoptedin which a coil spring is used in the second force-applying member thatpresses the heaters, the paired right and left clamps, theforce-applying member that grasps the optical fiber, and theforce-applying member of the lid, and the rotation support is arrangedon the same axis as that of the coil spring.

In the aforementioned configuration, a configuration may also be adoptedin which the camshaft is arranged among the rotation support that isdisposed under a device, the paired right and left clamps that aredisposed above a device, the heaters, and the lid.

Furthermore, in the aforementioned configuration, the invention providesan optical-fiber-spliced portion reinforcing heating devicecharacterized in that a pressing force that is to be applied to thesleeve by the second force-applying member is set to be greater than atension that is to be applied to the optical fiber by the firstforce-applying member, and in a state in which a tension is applied tothe optical fiber by the first force-applying member, one of the clampsapplying the tension is configured so that a backward movable range in adirection away from the heaters in the longitudinal direction of theoptical fiber is ensured, a forward movable range that allows movementto the heater side is ensured, and the clamp moves in a direction inwhich a tension that is applied to the optical fiber as a result ofpressing the sleeve by the heaters and by the second force-applyingmember is diminished.

The invention provides an optical-fiber-spliced portion reinforcingheating device including: a pair of right and left clamps thatrespectively grasp one portion of a coated portion of an optical fiberand the other portion thereof, the coated portion being exposed from asleeve, where optical fibers are fusion-spliced at which the coatedportion is removed and a coating-removed portion of a fusion-splicedportion and the coated portion of the optical fibers are covered withthe sleeve; a fifth force-applying member that is provided on at leastone of the clamps that are arranged to face each other with the opticalfiber interposed therebetween, sandwiches the optical fiber by use ofone of an elastic member and a magnetic member, and applies a pressingforce thereto; a first cam mechanism that is driven to rotate bycontrolling a motor; a mechanism that controls to grasp the opticalfiber by the clamps and by the pressing force of the fifthforce-applying member due to displacement of the first cam mechanism; atleast two or more heaters that are arranged to face each other so as tosandwich the optical fiber or the sleeve; a second force-applying memberthat applies a pressing force to at least one or more of the heaters viathe sleeve by use of one of an elastic member and a magnetic member, theheaters being arranged to face each other with the sleeve interposedtherebetween; a third cam mechanism that is disposed on a camshaft onwhich the first cam mechanism is provided or is disposed on the othercamshaft parallel to the camshaft, and is driven to rotate bycontrolling the motor; and a mechanism that controls to press the sleeveby the heaters and by the pressing force of the second force-applyingmember due to displacement of the third cam mechanism; wherein the samemotor controls a force of each of the force-applying members withrespect to the clamps and the heaters by the first and third cammechanisms.

In the aforementioned configuration, a configuration may also be adoptedin which, in two or more cam mechanisms used in the first cam mechanismand the third cam mechanism which are rotationally driven by the samemotor, a rotating drive force by the drive source is reduced bydetermining a timing of combining a positive driving that needs a rotarydrive torque and a negative driving that receives a torque to bediminished.

In the aforementioned configuration, a configuration may also be adoptedin which, in at least one of two or more cam mechanisms used in thefirst cam mechanism and the third cam mechanism, an auxiliary movablemember is disposed on the opposite side of each operation member withthe camshaft interposed therebetween, each operation member is coupledto the auxiliary movable member by use of one of an elastic member and amagnetic member, a rotary drive torque of each cam mechanism is reversedfrom positive driving to negative driving as a result of displacing theauxiliary movable member instead of each operation member in accordancewith a motion of each cam mechanism, and the positive driving and thenegative driving are thereby combined and diminished in the two or morecam mechanisms.

In the aforementioned configuration, a configuration may also be adoptedin which, regarding the paired right and left clamps and the heaters,one of them is movable, and the other of them is fixed.

In the aforementioned configuration, a configuration may also be adoptedwhich includes: a first force-applying member that presses at least oneof the clamps so as to apply a tension to the optical fiber by use ofone of an elastic member and a magnetic member; and a mechanism thatcontrols pull of the optical fiber, which is due to tensions of theclamps by the first force-applying member, based on operation ofgrasping the optical fiber by the clamps or operation of pressing thesleeve by the heaters, wherein the same motor controls the clamps or theheaters by the force of each of the force-applying members by use of thefirst and third cam mechanisms and control the tension mechanism byoperating the controlled clamps or the controlled heaters.

In the aforementioned configuration, a configuration may also be adoptedwhich includes: a first force-applying member that presses at least oneof the clamps so as to apply a tension to the optical fiber by use ofone of an elastic member and a magnetic member; a position limitingmember that is configured of a forward movement stopper or a backwardmovement stopper, which limits a forward movable range or a backwardmovable range of at least one of the paired right and left clamps; asecond cam mechanism that is to be rotationally driven by the motorcontrol, the second cam mechanism being disposed on the same camshaft asthose of the first and third cam mechanisms or disposed on the othercamshaft parallel to the camshaft; a mechanism in which displacement ofthe second cam mechanism controls pull of the optical fiber, which isdue to tensions of the clamps by the first force-applying member; and amechanism in which displacement of the second cam mechanism controlsmovement of the position limiting member, wherein the same motorcontrols the clamps and the heaters by the first to third cammechanisms.

In the aforementioned configuration, a configuration may also be adoptedwhich includes: a first force-applying member that presses at least oneof the clamps so as to apply a tension to the optical fiber by use ofone of an elastic member and a magnetic member; a third force-applyingmember that presses to apply a tension in an opposite direction relativeto the first force-applying member; a sixth cam mechanism that is to berotationally driven by the motor control, the second cam mechanism beingdisposed on the same camshaft as those of the first and third cammechanisms or disposed on the other camshaft parallel to the camshaft;and a mechanism in which displacement of the sixth cam mechanismcontrols an applied force of the first force-applying member or thethird force-applying member, wherein each of the first and thirdforce-applying members presses at least one of the clamps so as to applya tension to the optical fiber by use of one of an elastic member and amagnetic member, and the same motor controls the clamps, the heaters,and the applied force controller by the first, third, and sixth cammechanisms.

In the aforementioned configuration, a configuration may also be adoptedwhich includes: a lid that opens and closes the optical-fiber-splicedportion reinforcing heating device; a sixth force-applying member thatapplies a force of closing the lid thereto by use of one of an elasticmember and a magnetic member; a fourth cam mechanism that is disposed onthe same camshaft as those of the first and third cam mechanisms ordisposed on the other camshaft parallel to the camshaft; and a mechanismin which displacement of the fourth cam mechanism controls the lid to beopened or closed by an applied force of the sixth force-applying member,wherein the same motor controls the clamps, the heaters, and the lid bythe force of each of the force-applying members and by the first tofourth cam mechanisms.

In the aforementioned configuration, a configuration may also be adoptedin which at least any of the clamps, the heaters, and the lid isconfigured by a lever-shaped member that rotationally moves around arotation support parallel to the optical fiber and the sleeve or isprovided at a lever-shaped member.

In the aforementioned configuration, a configuration may also be adoptedin which a coil spring is used in the second force-applying member thatpresses the heaters, the paired right and left clamps, theforce-applying member that grasps the optical fiber, and theforce-applying member of the lid, and the rotation support is arrangedon the same axis as that of the coil spring.

In the aforementioned configuration, a configuration may also be adoptedin which the camshaft is arranged among the rotation support that isdisposed under a device, the paired right and left clamps that aredisposed above a device, the heaters, and the lid.

In the aforementioned configuration, a configuration may also be adoptedin which a pressing force that is to be applied to the sleeve by thesecond force-applying member is set to be greater than a tension that isto be applied to the optical fiber by the first force-applying member,and in a state in which a tension is applied to the optical fiber by thefirst force-applying member, one of the clamps applying the tension isconfigured so that a backward movable range in a direction away from theheaters in the longitudinal direction of the optical fiber is ensured, aforward movable range that allows movement to the heater side isensured, and the clamp moves in a direction in which a tension that isapplied to the optical fiber as a result of pressing the sleeve by theheaters and by the second force-applying member is diminished.

Effects of the Invention

According to the optical-fiber-spliced portion reinforcing heatingdevice of the invention, as a result of removing an excessive tensionthat is to be applied to the optical fiber when the sleeve is sandwichedbetween heaters and is heat-shrunk, breaking of the optical fiber ordegradation in long-term reliability is prevented, and a device isprevented from being larger in size.

Consequently, it is possible to heat-shrink the sleeve in a shorteramount of time with a high level of reliability, and anoptical-fiber-spliced portion reinforcing heating device having a highlevel of handleability can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an external appearance of anexample of a fusion splicer that is provided with anoptical-fiber-spliced portion reinforcing heating device according to anembodiment of the invention.

FIG. 2 is a perspective view showing an external appearance of anexample of the optical-fiber-spliced portion reinforcing heating deviceaccording to the embodiment of the invention.

FIG. 3 is a side view showing an external appearance of an example of afusion splicer that is provided with an optical-fiber-spliced portionreinforcing heating device according to the embodiment of the invention.

FIG. 4 is a breakaway view illustrating an example of the innerstructure of the optical-fiber-spliced portion reinforcing heatingdevice according to the embodiment of the invention.

FIG. 5 is a schematic view showing an example of a sleeve that is usedto reinforce an optical fiber spliced portion and is to be heat-shrunkby use of the optical-fiber-spliced portion reinforcing heating deviceaccording to the embodiment of the invention.

FIG. 6 is a schematic view illustrating an example of an operation ofthe optical-fiber-spliced portion reinforcing heating device accordingto the embodiment of the invention.

FIG. 7 is a schematic view illustrating an example of an operation ofthe optical-fiber-spliced portion reinforcing heating device accordingto the embodiment of the invention.

FIG. 8 is a schematic view illustrating an example of an operation ofthe optical-fiber-spliced portion reinforcing heating device accordingto the embodiment of the invention.

FIG. 9 is a schematic view illustrating an example of an operation ofthe optical-fiber-spliced portion reinforcing heating device accordingto the embodiment of the invention.

FIG. 10 is a schematic view illustrating an example of an operation ofthe optical-fiber-spliced portion reinforcing heating device accordingto the embodiment of the invention.

FIG. 11 is a schematic view illustrating an example of an operation ofthe optical-fiber-spliced portion reinforcing heating device accordingto the embodiment of the invention.

FIG. 12 is a schematic cross-sectional view illustrating the otherexample of the optical-fiber-spliced portion reinforcing heating deviceaccording to the embodiment of the invention.

FIG. 13 is a schematic cross-sectional view illustrating the otherexample of the optical-fiber-spliced portion reinforcing heating deviceaccording to the embodiment of the invention.

FIG. 14 view (a) is a schematic view illustrating the other example ofan operation of the optical-fiber-spliced portion reinforcing heatingdevice according to the embodiment of the invention. View (b) is aschematic view showing a structure including a retractable backwardmovement stopper. View (c) is a schematic view showing a structureincluding a retractable forward movement stopper.

FIG. 15 is a schematic view illustrating the other example of anoperation of the optical-fiber-spliced portion reinforcing heatingdevice according to the embodiment of the invention.

FIG. 16 is a schematic view illustrating the other example of anoperation of the optical-fiber-spliced portion reinforcing heatingdevice according to the embodiment of the invention.

FIG. 17 is a schematic view illustrating the other example of anoperation of the optical-fiber-spliced portion reinforcing heatingdevice according to the embodiment of the invention.

FIG. 18 is a schematic view illustrating the other example of anoperation of the optical-fiber-spliced portion reinforcing heatingdevice according to the embodiment of the invention.

FIG. 19 is a timing chart illustrating a series of operation timings inthe optical-fiber-spliced portion reinforcing heating device.

FIG. 20 is a timing chart illustrating a series of operation timings inthe optical-fiber-spliced portion reinforcing heating device.

FIG. 21 is a schematic view illustrating the other example of anoperation of the optical-fiber-spliced portion reinforcing heatingdevice according to the embodiment of the invention.

FIG. 22 is a schematic view illustrating the other example of anoperation of the optical-fiber-spliced portion reinforcing heatingdevice according to the embodiment of the invention.

FIG. 23 is a front view illustrating an external appearance of anexample of the optical-fiber-spliced portion reinforcing heating deviceaccording to the embodiment of the invention.

FIG. 24 is a schematic view showing an example of an operation of theoptical-fiber-spliced portion reinforcing heating device according tothe embodiment of the invention and is a cross-sectional view takenalong the cross-section line A-A shown in FIG. 23.

FIG. 25 is a schematic view showing an example of an operation of theoptical-fiber-spliced portion reinforcing heating device according tothe embodiment of the invention and is a cross-sectional view takenalong the cross-section line B-B shown in FIG. 23.

FIG. 26 is a schematic view showing an example of an operation of theoptical-fiber-spliced portion reinforcing heating device according tothe embodiment of the invention and is a cross-sectional view takenalong the cross-section line C-C shown in FIG. 23.

FIG. 27 is a schematic view showing an example of an operation of theoptical-fiber-spliced portion reinforcing heating device according tothe embodiment of the invention and is a cross-sectional view takenalong the cross-section line D-D shown in FIG. 23.

FIG. 28 is a schematic view showing an example of an operation of theoptical-fiber-spliced portion reinforcing heating device according tothe embodiment of the invention and is a cross-sectional view takenalong the cross-section line E-E shown in FIG. 23.

FIG. 29 is a breakaway view partially illustrating the relevant part ofthe optical-fiber-spliced portion reinforcing heating device accordingto the embodiment of the invention.

FIG. 30 is a breakaway view partially illustrating the relevant part ofthe optical-fiber-spliced portion reinforcing heating device accordingto the embodiment of the invention.

FIG. 31 is a chart illustrating the relationship between the pressingforce and the shrinking time when a reinforcement sleeve of the opticalfiber spliced portion is pressed while being heated by use of theoptical-fiber-spliced portion reinforcing heating device.

FIG. 32 is a cross-sectional view schematically illustrating a series ofoperations when the reinforcement sleeve of the optical fiber splicedportion is pressed while being heated by use of a conventionaloptical-fiber-spliced portion reinforcing heating device.

FIG. 33 is a schematic view showing illustrating the operations when thereinforcement sleeve of the optical fiber spliced portion is pressedwhile being heated by use of a conventional optical-fiber-splicedportion reinforcing heating device, (a) is a schematic view illustratinga slack state of an optical fiber, and (b) is a cross-sectional viewshowing a state in which a sleeve is sandwiched between heaters.

FIG. 34 is a schematic view illustrating the other example of theoptical-fiber-spliced portion reinforcing heating device according tothe embodiment of the invention.

FIG. 35 is a schematic view illustrating an operation of theoptical-fiber-spliced portion reinforcing heating device shown in theprevious figure.

FIG. 36 is a schematic view continuous with the previous figure,illustrating an operation of the optical-fiber-spliced portionreinforcing heating device.

FIG. 37 is a schematic view continuous with the previous figure,illustrating an operation of the optical-fiber-spliced portionreinforcing heating device.

FIG. 38 is a schematic view continuous with the previous figure,illustrating an operation of the optical-fiber-spliced portionreinforcing heating device.

FIG. 39 is a schematic view continuous with the previous figure,illustrating an operation of the optical-fiber-spliced portionreinforcing heating device.

FIG. 40 is a schematic view illustrating the other example of theoptical-fiber-spliced portion reinforcing heating device according tothe embodiment of the invention.

FIG. 41 is a schematic view illustrating an operation of theoptical-fiber-spliced portion reinforcing heating device shown in FIG.34.

FIG. 42 is a schematic view continuous with the previous figure,illustrating an operation of the optical-fiber-spliced portionreinforcing heating device.

FIG. 43 is a schematic view continuous with the previous figure,illustrating an operation of the optical-fiber-spliced portionreinforcing heating device.

FIG. 44 is a schematic view continuous with the previous figure,illustrating an operation of the optical-fiber-spliced portionreinforcing heating device.

FIG. 45 is a schematic view illustrating the other example of theoptical-fiber-spliced portion reinforcing heating device according tothe embodiment of the invention.

FIG. 46 is a schematic view illustrating an operation of theoptical-fiber-spliced portion reinforcing heating device shown in theprevious figure.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an optical-fiber-spliced portion reinforcing heating deviceaccording to a preferred embodiment related to the invention is adopted,and each constitution thereof will be described in detail with referenceto drawings.

<Optical Fiber Fusion Splicer>

FIG. 1 shows an example of a fusion splicer including anoptical-fiber-spliced portion reinforcing heating device 1 according tothe invention.

The fusion splicer A shown in FIG. 1 includes: a fusion splicing unit110 that carries out fusion splicing an optical fiber; and theoptical-fiber-spliced portion reinforcing heating device 1 (reinforcingheating device) that is used to heat shrink a reinforcement sleeve thatcovers the fusion-spliced optical fiber (also refer to FIG. 2).

Moreover, the fusion splicer A is provided with an indicator 120 thatdisplays a variety of information or the like for an operator, anoperation unit 130 that is used to set, for example, conditions, or thelike in addition to the aforementioned reinforcing heating device 1 andthe fusion splicing unit 110.

Furthermore, in the fusion splicer A shown as an example in the drawing,a built-in device (not shown in the figure), for example, a means, acontroller, or the like, which is used to comprehensively drive them inaddition to the reinforcing heating device 1 or the fusion splicing unit110 are arranged in a substantially cube-shaped body part 101.

In addition, a plurality of legs 102 (four legs are shown in the drawingas an example and part of them is not shown in the figure) are providedunder the body part 101.

Various display system such as liquid crystal, organic EL, or electriclight may be adopted as the indicator 120.

Furthermore, the fusion splicer A is provided with a movable panel 103at the fore side of the body part 101, and the indicator 120 or theoperation unit 130 is disposed above the panel 103.

The panel 103 is coupled to the body part 101 via a rotation shaft 101 ain the horizontal direction is provided at the upper portion of the bodypart 101 and can allow the indicator 120 to be directed to an optionaldirection in a predetermined angle range by movement of the panel 103,which is not particularly shown in the figure.

The operator can move the panel 103 so that the indicator 120 is in aneasily viewable direction.

In the example as shown in the perspective view shown in FIG. 1 and theside view shown in FIG. 3, the reinforcing heating device 1 is arrangedat the position which is a rear side of the fusion splicer A, and thefusion splicing unit 110 is disposed in front of the reinforcing heatingdevice 1.

Here, regarding front, back, left, and right in the explanation in theembodiment, in the situation where an operator uses the fusion splicer Aincluding the above-mentioned reinforcing heating device 1, the sidethat faces the operator is referred to as the front side (the left sidein FIG. 3), the rear side of the fusion splicer A as seen from theoperator is referred to as the back side (the right side in FIG. 3), andthe right and the left of the operator are referred to as the right andthe left.

<Sleeve Used to Reinforce an Optical Fiber Spliced Portion>

As shown in FIG. 5 cases (a) and (b), a sleeve 12 that is heat-shrunk bythe reinforcing heating device 1 according to the invention andreinforces an optical fiber spliced portion is provided so as to covertensile strength members 13A and 13B and an optical fiber 11 (splicedportion 11A) at the position of the spliced portion 11A where theoptical fibers 11 are fusion-spliced to each other.

Generally, the foregoing sleeve 12 is called by various names such as anoptical fiber reinforcement member, a heat shrinkable tube, a heatshrinkable sleeve, a reinforcement sleeve, and all of them have a commonfunction.

Particularly, in FIG. 5 cases (a) and (b), for convenience, the samereference numeral is added to all sleeves.

As shown in an example in FIG. 5 case (a), in the case where the sleeve12 is used for a single-core optical fiber spliced portion, an innertube 12 b that is formed of a cylindrical hot melt tube and is in astate of covering the spliced portion 11A of the optical fiber 11 and atensile strength member 13A that is formed of a cylindrical hard coremade of a SUS or the like are arranged inside an outer tube 12 a formedof a heat shrinkable tube.

Furthermore, as shown in FIG. 5 case (b), in a state in which the sleeve12 is used for a spliced portion of a multi-core optical fiber(multi-core ribbon), an inner tube 12 b that is formed of an ellipticcylindrical hot melt tube and is in a state of covering the splicedportion 11A of the optical fiber 11 and a tensile strength member 13Bthat is formed of a semicircular-column shaped hard core made of glassor the like are arranged inside an outer tube 12 a formed of a heatshrinkable tube.

Here, as the reason that a glass hard core shown in FIG. 5 case (b) isused as the tensile strength member 13B that is inserted into the sleeve12 for reinforcement of the spliced portion of the multi-core opticalfiber, the reason described below is adopted.

Generally, in a fusion splicer, an optical fiber is subjected to atensile test after the optical fibers are spliced, and the reliabilitythereof (for example, the presence or absence of damages to glass) isthereby evaluated.

In the case of a single-core optical fiber, even in cases where a degreeof elasticity is large and an inexpensive SUS is used as a tensilestrength member, since the reliability thereof is evaluated by thetensile test, it is possible to determine if it is appropriate.

However, in the case of a multi-core ribbon optical fiber, since atension is only applied to one fiber that is shortest in the multi-coreoptical fibers, it is not possible to presume that the reliabilitythereof is ensured.

Consequently, for reinforcement of the spliced portion of the multi-coreoptical fiber, a glass material having a low degree of elasticitysimilar to that of an optical fiber is used as tensile strength member;however, it is a little expensive.

Particularly, hereinafter, in order to provide a clear understanding,the outer tube and the inner tube are simply referred to as the sleeve12 without discriminating them, and additionally drawings are explainedis the same way.

<Optical-Fiber-Spliced Portion Reinforcing Heating Device>

First Embodiment

Hereinafter, an optical-fiber-spliced portion reinforcing heating deviceaccording to a first embodiment of the invention will be described indetails mainly using schematic views shown in FIGS. 5 to 17.

In other cases, the configurations which are not shown in schematicviews of FIGS. 5 to 17 will be described using a breakaway view shown inFIG. 4 or the like which is illustrated in a second embodiment accordingto the invention.

Additionally, configurations that are common to those of a reinforcingheating device according to a second embodiment, which will beparticularly described later, will be suitably described with referenceto FIG. 4 or the like in this embodiment; in addition, even whereplacements or the like of configurations of embodiments are differentfrom each other, elements having the same function may be represented bythe same reference numerals in the description.

Furthermore, each of drawings which will be referred in the explanationdescribed below schematically illustrates a reinforcing heating device.Therefore, positional relationships of the drawings may be differentfrom each other in the horizontal direction or the vertical direction inthe drawings.

As shown in FIG. 6 or the like (also, partially refer to FIG. 4), thereinforcing heating device 1 according to the embodiment includes: apair of right and left clamps 2 (2A, 2B) grasp one portion of the coatedportion exposed from the sleeve 12 and the other portion thereof wherethe optical fibers 11 are fusion-spliced to each other at which a coatedportion is removed and a coating-removed portion and the coated portionof the fusion spliced portion 11A of the optical fiber 11 are coveredwith the sleeve 12; two heaters 3 (3A, 3B) that are disposed so as toface each other so as to sandwich the optical fiber 11 or the sleeve 12;a first force-applying member 41 that presses at least one of the clamps2, for example, the clamp 2A shown in the drawing so as to apply atension to the optical fiber 11 by use of one of an elastic member and amagnetic member; and a second force-applying member 42 that applies apressing force to at least one or more of the paired heaters 3A and 3Bby use of one of an elastic member and a magnetic member with the sleeve12 interposed therebetween in accordance with control of a motor 6serving as a drive source where the heaters are arranged opposite toeach other with the sleeve 12 interposed therebetween.

Moreover, in the reinforcing heating device 1, the pressing force withrespect to the sleeve 12 by the second force-applying member 42 is setto be greater than the tension to the optical fiber 11 by the firstforce-applying member 41, in a state in which a tension is applied tothe optical fiber 11 by the first force-applying member 41, a backwardmovable range K is ensured in a direction in which one clamp 2A thatapplies a tension thereto moves separately from the heaters 3 in thelongitudinal direction of the optical fiber 11, and a forward movablerange Z is ensured in which the clamp can move to the heater side 3.

Consequently, in the reinforcing heating device 1, the clamp 2A isconfigured to move in the direction in which the tension that is to beapplied to the optical fiber 11 as a result of pressing the sleeve 12 bythe heaters 3 and by the second force-applying member 42 is diminished.

Furthermore, the reinforcing heating device 1 is provided with a lid 10that carries out opening and closing of the inside of device when theoptical fiber 11 is set to this reinforcing heating device.

Additionally, each of the above-mentioned structures is attached to ahousing 5 or accommodated in the inside of the housing 5.

In addition, the sleeve 12 may cover a coating-removed portion and acoated portion of the optical fiber 11 or only cover the coating-removedportion.

As shown in FIG. 6 or the like, the clamps 2 (2A, 2B) are a pair ofright and left clamps which are constituted of the clamp 2A that graspsone of the optical fiber 11 and the clamp 2B that grasps the other ofthe optical fiber 11.

The clamps 2 are configured to be able to sandwich and grasp (clamp) theoptical fiber 11 by use of a force-applying member such as a torsioncoil spring or a double torsion spring (for example, a force-applyingmember of 2 a shown in FIG. 34) and are placed at both sides of theheaters 3 in the longitudinal direction of the optical fiber 11 shown asan example in the drawing.

Additionally, as shown in FIG. 6 or the like, the clamp 2A that is oneof the right and left clamps 2 that are arranged to form a pair thereofis configured to be openable and closable and the clamp 2B that is theother thereof is configured to be the same.

Furthermore, one of the clamps 2 slidably moves in the longitudinaldirection of the optical fiber 11 and the clamp 2A is configured to beable to apply a tension to the optical fiber 11 by use of the firstforce-applying member 41 formed of a permanent magnet as an exampleshown in FIG. 6 or the like.

The clamps 2 are provided for preventing the displacement between theposition of the sleeve 12 and the position of the spliced portion 11A ofthe optical fiber 11 in the case where a tension is applied to theoptical fiber 11 before heat shrinking is carried out, generally, theclamps are located at two positions, that is, at both sides of theheaters 3.

Moreover, a grasping rubber which is used to directly grasp the opticalfiber 11 and is not shown in FIG. 6 or the like is provided on thesurface of each of the paired right and left clamps 2A and 2B (refer toFIG. 29).

The heaters 3 (3A, 3B) is used to press and heat-shrink the sleeve 12and is generally referred to as a name such as a heater, a heatgeneration unit, a heat generation source, a heat generation body, aheat source, a heating section, a heating source, a heating member, orthe like.

The heaters 3 serving as two heaters 3A and 3B are opposed and arrangedso as to sandwich the optical fiber 11 or the sleeve 12 and are therebyconfigured to be able to sandwich and press the sleeve 12 so that oneheater 3A is configured to be openable and closable and the heater 3B isfixed.

Furthermore, the openable-and-closable heater 3A is configured to pressthe sleeve 12 in a direction in which the sleeve is sandwiched andpressed by the second force-applying member 42 configured by a doubletorsion spring as shown in FIG. 4.

In addition, as shown in FIG. 6 or the like as an example, the twoheaters 3A and 3B are attached to surfaces of heater attachment bases31A and 31B, respectively.

The heaters 3 are not particularly shown in the figure; however,generally, it is preferable to use a plurality of heater circuitpatterns.

Furthermore, a polyimide film heater that is adhesively attached to ametal sheet as well as a ceramic heater that is adhesively attached to ametal sheet is preferably used as the heaters 3 as an example since theentire surface of them can be subjected to folding.

In this case, a configuration can be adopted in which, for example, two,three, or more circuit patterns formed of a polyimide film heater areimplanted into a plate-shaped metal sheet.

In the embodiment, a configuration is adopted which sandwiches thesleeve 12 by only driving one heater 3A; however, it is not limited tothis, for example, a further powerful pressing force can also begenerated by driving both two heaters.

However, in the case of driving both two heaters, since there is aconcern that the mechanism thereof becomes complicated and costincreases, it is not preferable in any way.

Moreover, even in the structure that drives only one heater 3A such asthe embodiment, since a sufficient pressing force with respect to thesleeve 12 is obtained and there is also an advantage described below,the above-mentioned configuration is preferably adopted.

Firstly, in the case where one heater 3A is only openable and closable,since a drive mechanism of the other heater 3B is not necessary and anelastic member such as a heater attachment base which will beparticularly described later or a double torsion spring that is used topress the sleeve 12 is not necessary at this position, it is possible toreduce the number of parts and the cost therefor.

Furthermore, it is possible to reduce the displacement from the centerline S of the optical fiber 11 when the heaters 3 presses the sleeve 12.

The reason is that, the other heater 3B is fixed, as compared with acase where both heaters are openable and closable, it is not necessaryfor the applied forces of the elastic members to be balanced,particularly when the sleeve 12 is set adjacent to the fixed-side heater3B, it is possible to minimize the displacement of the optical fiber 11.

In details, as a result of providing the optical fiber 11 and the sleeve12 shown in FIG. 6 to be adjacent to the fixed-side heater 3B such that,for example, the sleeve 12 comes into contact therewith and grasping theoptical fiber 11 by the clamps 3 in this state, it is possible tominimize the displacement of the optical fiber 11 during pressingthereof by the heaters 3.

At this time, when heat-shrinkage of the sleeve 12 begins, the positionsof the optical fiber 11 and the sleeve 12 gradually move to thefixed-side heater 3B.

Subsequently, when the sleeve 12 is completely heat-shrunk, it is notpossible to avoid the position of the optical fiber 11 from beingdisplaced from the center line S to the other heater 3B.

However, in this case, the displacement of the optical fiber 11 is asubstantially half of the diameter of the sleeve 12, substantially,which is a degree of decrease in the diameter due to the heat shrinkage.

Additionally, in the embodiment, similar to the case of the reinforcingheating device shown in FIG. 4 as an example, with respect to theabove-mentioned paired heaters 3 and the paired right and left clamps 2,it is possible to carry out opening and closing by driving one heater 3Aand opening and closing by driving one clamp 2A by use of the samecamshaft 7 (on the same axis) by the motor 6 that is the same drivesource.

In the case of adopting the foregoing configuration, the effect isobtained that a sequence of control such as grasping and removing of theoptical fiber 11 by opening and closing by use of the pair of right andleft clamps 3, control of a tension that is to be applied to the opticalfiber 11, and heat shrinking of the sleeve 12 by pressing by the pair ofheaters 3 becomes easy.

In addition, in the embodiment, as shown in FIGS. 6 to 11, a drivecontrol of operations of opening and closing the paired right and leftclamps 2A and 2B is carried out by a first cam mechanism 71 that isprovided in the camshaft 7, and a drive control of one heater 3A that isconfigured to be openable and closable is carried out by a third cammechanism 73.

Furthermore, in the embodiment, a second cam mechanism 72 that isprovided in the camshaft 7 is configured to function as a backwardmovement stopper that restricts a movement of one clamp 2A in a backwarddirection where the clamp slidably moves in the longitudinal directionof the optical fiber 11.

In the invention, the cam mechanism may be simply referred to as a “cam”or “cam member”.

Moreover, as described above, one clamp 2A is pressed by the firstforce-applying member 41 that is configured by an elastic member such asa spring, a rubber, or a sponge, or a magnetic member such as apermanent magnet or an electromagnet in the longitudinal direction ofthe optical fiber 11 and in the backward movement direction, and isconfigured to be able to apply a tension to the optical fiber 11.

Consequently, the embodiment provides the backward movable range K inwhich a slack of the optical fiber 11 is removed and the forward movablerange Z in which, even in the case where an excessive tension is appliedto the optical fiber 11 by pressing one heater 3A, the tension can beabsorbed.

Furthermore, in the reinforcing heating device 1, the paired right andleft clamps 2A and 2B or one heater 3A does not carry out grasping,opening, and closing operations or a pressing operation by a drivingpower that is directly transmitted through the above-mentioned motor 6or each cam mechanism, and each force-applying member that is configuredby an elastic member such as a spring, a rubber, or a sponge, or amagnetic member such as a permanent magnet or an electromagnet pressesthe optical fiber 11 or the sleeve 12.

Particularly, a double torsion spring is used as the secondforce-applying member 42 that presses one heater 3A in the example shownin FIG. 4, and a torsion coil spring is used as a fifth force-applyingmember 45 that presses the openable-and-closable side of the pairedright and left clamps 2A and 2B in the example shown in FIG. 29.

(Example of Operation of Reinforcing Heating Device)

As described above, in the reinforcing heating device 1 described in theembodiment, an applied force of the second force-applying member 42 thatpresses one heater 3A is set to a large pressing force such that, whenthe sleeve 12 is pressed by the second force-applying member 42 and theheater 3A, the applied force causes the optical fiber 11 to be displacedfrom the central axis line S (refer to FIG. 12 or the like) of theoptical fiber 11 pulled by the first force-applying member 41.

Additionally, in a state in which a tension is applied to the opticalfiber 11 by the first force-applying member 41, the backward movablerange K is ensured in a direction in which one clamp 2A that applies atension thereto moves separately from the heaters 3 in the longitudinaldirection of the optical fiber 11, and the forward movable range Z isensured in which the clamp can move to the heater side 3.

Furthermore, the clamp 2A is configured to move in the direction inwhich the tension that is to be applied to the optical fiber 11 as aresult of pressing the sleeve 12 by the heaters 3 and by the secondforce-applying member 42 is diminished.

Steps in the case of heat-shrinking the sleeve 12 in a state of coatingthe spliced portion 11A of the optical fiber 11 by use of thereinforcing heating device 1 provided with the aforementionedconfiguration and effects that can diminish and remove a tension will bedescribed below with reference to mainly FIGS. 4, and 6 to 11.

FIGS. 6 to 11 are schematic views showing the situations as seen fromthe upper side of the reinforcing heating device 1.

Particularly, in order to provide a clear understanding, part ofconfiguration shown in FIGS. 6 to 11 is omitted with respect to thebreakaway view shown in FIG. 4, and the same configurations are appliedin the explanation below.

As shown in FIG. 6, the optical fiber 11 is inserted into the sleeve 12,the camshaft 7 is disposed at the lower side of the optical fiber 11 (adeep direction in the drawing).

Two heaters 3A and 3B that is used to press the sleeve 12 are aredisposed at a substantially center portion shown in FIG. 6, the rearside thereof (the upper side of FIG. 6) is driven as anopenable-and-closable heater 3A, and the front side thereof (the lowerside of FIG. 6) is a fixed-side heater 3B.

Regarding the paired right and left clamps 2A and 2B, the rear sidethereof (the upper side of FIG. 6) is driven as an openable-and-closableclamp, and the front side thereof (the lower side of FIG. 6) is a fixedclamp.

One clamp 2A can slidably move in the longitudinal direction of theoptical fiber 11 by a slide mechanism 21 that is configured by, forexample, a bearing or the like.

In the drawing shown as an example, the slide mechanism 21 is providedon the clamp that is in front of the clamp 2A, and the configuration inwhich slide movement is possible is realized while the front and rearsides thereof coordinately move.

Moreover, in the drawing shown as an example, the first force-applyingmember 41 is provided by disposing the total four magnets (magneticmember) near the slide mechanism 21 provided at one clamp 2A, the clamp2A is in a state of being pulled in the left direction in the drawing,that is, in the backward movement direction in which it is possible toapply a tension to the optical fiber 11.

As described above, this tension is a weak force such as several tens ofgf.

On the other hand, a strong force such as several hundreds of gf isapplied to each of the openable-and-closable side of the paired rightand left clamps 2A and 2B and one heater 3A by the fifth force-applyingmember 45 (refer to FIG. 29) and the second force-applying member 42;however, they are in a state of being opened by pressure of the firstcam mechanism 71 the third cam mechanism 73 which are provided in thecamshaft 7 in FIG. 6.

Additionally, the cam mechanisms such as the first cam mechanism 71, thethird cam mechanism 73, and the like are different from each other inconfiguration.

Next, as shown in FIG. 7, when the camshaft begins to rotate, firstly,the openable-and-closable clamp of the paired right and left clamps 2Aand 2B is closed, and the first cam mechanism 71 and the paired rightand left clamps 2A and 2B are in a non-contact state.

As stated above, since the first cam mechanism 71 and theopenable-and-closable side of the paired right and left clamps 2A and 2Bare in a non-contact state, the paired right and left clamps 2A and 2Bgrasp the optical fiber 11 by a pressing force of several hundreds of gfby the fifth force-applying member 45.

Subsequently, as shown in FIG. 8, when the camshaft 7 further rotates,the second cam mechanism 72 that is positioned close to one clamp 2A andboth the fixed-side and the openable-and-closable side of one clamp 2Aare in a non-contact state, the entire one clamp 2A is movable in thebackward movement direction (the left side in the drawing), andtherefore, a tension due to the first force-applying member 41 isapplied to the optical fiber 11.

At this time, a slack of the optical fiber 11, that is, the lowering ofthe position of the sleeve 12 in the vertical direction thereof, can beremoved by slide movement of one clamp 2A in the backward movementdirection.

Here, the backward movable range K occurs and is ensured in addition tothe forward movable range Z in one clamp 2A.

Consequently, one clamp 2A is in a state of being capable of moving backand forth in the longitudinal direction of the optical fiber 11.

Because of this, it is possible to control a tension to be constant in astate in which a slack of the optical fiber 11 does not occur.

After that, as shown in FIG. 9, the camshaft 7 further rotates, thethird cam mechanism 73 does not comes into contact with the heaterattachment base 31A, and the sleeve 12 is sandwiched between two heaters3A and 3B that are disposed on surfaces of the heater attachment bases31A and 31B and is in a state of being pressed by a pressing force ofseveral hundreds of gf by the second force-applying member 42.

In this state, the rotation of the camshaft 7 is stopped.

In such a state, an operation of heat shrinking the sleeve 12 begins bytwo heaters 3A and 3B.

Before long, as shown in FIG. 10, shrinkage of the sleeve 12 iscompleted.

At this time, during shrinkage of the sleeve 12, the sleeve 12 and theoptical fiber 11 move in the direction of the other heater 3B whilebeing pressed by a force of several hundreds of gf. However, since oneclamp 2A slidably moves in the forward movement direction (the rightside in the drawing), a tension that is to be applied to the opticalfiber 11 can be maintained constant such as several tens of gf.

The amount of time for heating the sleeve 12 in a pressing state asshown in FIG. 10 varies depending on the kinds of sleeve 12.

For this reason, in advance, an operator specifies the kinds of sleevein a heating controller which is not shown in the figure.

As the heating controller performs a control of extension or shorteningof the heating time which is due to an outdoor temperature or a batteryvoltage based on the specified information according to the kinds ofsleeve, shrinkage of the sleeve 12 is carried out at an optimaltemperature (generally, 200 to 240° C.) and for an optimal heating time.

This is a typical example of heating control.

After heating by the two heaters 3 is carried out for an optimal time,the heating by the heaters 3 are stopped.

Subsequently, as shown in FIG. 11, as the camshaft 7 further rotates,the openable-and-closable side of the paired right and left clamps 2Aand 2B is opened by the first cam mechanism 71, the optical fiber 11 isreleased from a grasping state.

Moreover, as the heater attachment base 31A to which one heater 3A isattached is opened by pressure of the third cam mechanism 73, the sleeve12 is separated from the two heaters 3A and 3B and is in a state ofbeing released from pressure.

Furthermore, in order to shorten the amount of time of heating thesleeve by the reinforcing heating device, shortening of the cooling timeis also of importance.

As the sleeve 12 moves separately from the heaters 3, heat transfer ofremaining heat of the heaters 3 to the sleeve 12 is blocked;furthermore, as a cold air flows into the internal side of thereinforcing heating device 1, it is possible to rapidly cool down thesleeve 12 having a high temperature which is due to heating.

Additionally, as a result of adopting a constitution that is providedwith a small fan or the like, a cold air is effectively introducedthereinto from outside, and it is possible to further reduce the coolingtime.

In the embodiment, as a result of ensuring the backward movable range Kof one clamp 2A serving as a slide movable side as described above, evenin a case where the optical fiber 11 is set (grasped) so as to have aslack, a tension is applied to the optical fiber 11, and it is possibleto eliminate the slack.

Accordingly, the sleeve 12 is not displaced downward in, for example,the vertically downward direction, the sleeve 12 is held by the heater3A near a substantially center thereof and can be efficiently heated.

Moreover, as a result of ensuring the forward movable range Z of oneclamp 2A, even where the optical fiber 11 receives a large pressure fromthe heater 3, one clamp 2A moves in a forward movement direction, andtherefore, it is possible to protect the optical fiber 11 while anexcessive tension is not applied thereto.

In addition, the invention is not limited to the aforementioned example.

For example, a plurality of heater circuits which are configured by aceramic heater may be implanted into the two heaters 3A and 3B, or afilm heater may also be adopted, and furthermore, a constitution using ametal heat-transfer plate to which such heater circuits are attached mayalso be adopted.

Furthermore, a constitution in which a plurality of heater circuits areprovided on both two heaters 3A and 3B may also be adopted, or aconstitution in which it is provided on only one side thereof may alsobe adopted.

Moreover, one heater 3A is only driven in the constitution of theembodiment; however, a constitution in which both two heaters 3A and 3Bare driven may also be adopted.

In addition, a method of driving a heater is not particularly limited,for example, a slide drive unit may be adopted, and a rotational slidesystem in which a fulcrum point is located at the position that is farfrom the heater portion may also be adopted as an example shown in FIG.4 or the like.

Additionally, the second force-applying member 42 that presses oneheater 3A may use a repulsion force by a magnet (magnetic member) or mayuse a torsion coil spring or the like as an example shown in FIG. 4 orthe like.

Furthermore, in the case where an electromagnet is used as the secondforce-applying member 42, the electrical current that is applied to theelectromagnetic coil is a drive source, and a constitution whichcontrols an applied force by the electromagnet in accordance with theapplied current and presses one heater 3A may also be adopted.

Also, the slide portion of a slide movable clamp is not particularlylimited. As shown in FIG. 6 or the like, the left clamp 2A may also beconfigured to be only slide-movable or both the paired right and leftclamps 2A and 2B may also be configured to be slide-movable.

In addition, a slide mechanism of the slide movable clamp is notparticularly limited. For example, a slide drive unit using an expensivebearing shown in FIG. 6 or the like may also be adopted or a rotationalslide system in which a fulcrum point is located at the position that isfar from the clamp may also be adopted as an example shown in FIG. 4 orthe like.

Furthermore, the first force-applying member 41 that presses the slideportion of the slide movable clamp by a force for applying a tension tothe optical fiber 11 is not particularly limited. A magnet (magneticmember) as shown in FIG. 6 or the like may also be used, or an elasticmember such as a compression coil spring may also be used.

Additionally, the openable-and-closable portions of the paired right andleft clamps 2A and 2B is not particularly limited, the front sidethereof or the rear side thereof may be only opened and closed, and boththe front and back sides may also be opened and closed.

Moreover, the fifth force-applying member 45 (refer to FIG. 29)providing a force that grasps the optical fiber 11 at theopenable-and-closable sides of the paired right and left clamps 2A and2B is not particularly limited; and the member may use a repulsion forceby a magnet (magnetic member) or may use a torsion coil spring or thelike as an example shown in FIG. 4 or the like.

Additionally, each cam mechanism is not also particularly limited tothis, as described above, a constitution in which a plurality of cammechanisms are provided on the same the camshaft 7 and on the same axismay also be adopted, or a constitution in which a plurality of axes areprovided using a plurality of camshafts may also be adopted.

Furthermore, the cam mechanism is not only limited to the above, aforward-and-rearward drive mechanism using, for example, a screwmechanism (including a micrometer), a magnetic force drive mechanismthat turns on or off an electromagnet, a drive mechanism using a leverand a solenoid, or the like may be used.

(Other Example of Operation of Reinforcing Heating Device)

Next, one modified example according to the embodiment will bedescribed.

In the embodiment, in order to prevent the lowering of the sleeve 12 inthe vertically downward direction which is due to a slack of the opticalfiber 11 as examples shown in FIGS. 12 and 13, a configuration of atleast one of the two heaters may be configured to have an L-shape incross section which shown as an example in the drawing.

In an example shown in the drawing, a fixed-side heater 93B of twoheaters 93A and 93B is formed in an L-shape. FIGS. 12 and 13 show thecase where a sleeve 12 having a large diameter is provided and the casewhere a sleeve 12 having a small diameter is provided, respectively.

In the case of the foregoing configurations, there are disadvantagesthat the heat capacity increases as the heater becomes larger, and arate of temperature increase thereby becomes low, or in the case wherethe sleeve 12 having a small diameter is disposed as shown in FIG. 13 asan example, the position of the sleeve 12 becomes low, and heatingcannot be carried out at the center of the heater.

However, as a result of adopting the heater structure shown in FIGS. 12and 13, it is also possible to omit the first cam mechanism 71 in theconstitution of the reinforcing heating device as illustrated in FIGS. 4and 6 to 11, and a simplified structure can be achieved.

In other cases, as a configuration for preventing the sleeve 12 fromlowering, not only the aforementioned heater which is formed in anL-shape but also a constitution in which, for example, a metal sheetformed in an L-shape is provided may be adopted.

As stated above, it is not necessary for the L-shaped constitution to beapplied to part of the heater, and the constitution may be a member thatis independent from the heater.

Steps in the case where the above-mentioned constitution that preventthe optical fiber 11 from lowering is adopted and effects of diminishingand reducing the strong pressing force by the heaters will be describedwith reference to mainly FIGS. 14 to 17 that show schematic views (alsorefer to FIG. 4).

A reinforcing heating device shown in FIGS. 14 to 17 is different fromthe aforementioned reinforcing heating device shown in FIGS. 6 to 11 inthat a cam mechanism (the second cam mechanism 72) that restricts oneclamp 2A from moving in the backward movement direction is not presentand in that, since this cam mechanism is not provided, one clamp 2Acomes into contact with a stopper 51 in the backward movement directionin an initial state, and a backward movable range is not provided.

In addition, in the drawing shown as an example, for convenience ofexplanation, an L-shaped heater is not shown in the figure (refer toFIGS. 12 and 13).

First of all, as shown in FIG. 14, the optical fiber 11 having a splicedportion that is covered with the sleeve 12 is inserted between thepaired right and left clamps 2A and 2B.

Subsequently, as shown in FIG. 15, rotation of the camshaft 7 isstarted, the openable-and-closable clamp of the paired right and leftclamps 2A and 2B is closed, the first cam mechanism 71 and the pairedright and left clamps 2A and 2B are in a non-contact state, and theclamps 2A and 2B grasp the optical fiber 11 by a pressing force ofseveral hundreds of gf.

At this time, the sleeve 12 is supported by the fixed-side heater 93Bwhich is configured to have an L-shape and is not particularly shown inthe figure, and the sleeve is held on the surface of the heater at asubstantially proper position for heating.

In contrast, in this state, a slack of the optical fiber 11 remains.

Next, as shown in FIG. 16, when the camshaft 7 further rotates, thesleeve 12 is pressed by the openable-and-closable heater 93A beforebeing heated, the sleeve moves to the fixed-side heater 93B, and theoptical fiber 11 also moves in accordance with this.

Alternatively, the sleeve 12 is deformed after the start of heating bythe heaters 93A and 93B, and the optical fiber 11 also moves inaccordance with this.

According to the above-mentioned operation, a slack of the optical fiber11 is removed, and one clamp 2A slidably moves in the forward movementdirection in a form in which the optical fiber 11 is pulled.

Therefore, as shown in the drawing, the backward movable range K inaddition to the forward movable range Z is ensured in one clamp 2A.

For this reason, since one clamp 2A is in a state of being capable ofmoving forth and back in the longitudinal direction of the optical fiber11, a tension can be controlled to be constant in a state in which aslack is not present in the optical fiber 11.

The later steps after the above are the same as in the case of the aboveexplanation with reference to FIGS. 6 to 11 and an operation ofshrinking the sleeve 12 by heating by use of the heaters 93A and 93B iscarried out.

Next, the shrinkage of the sleeve 12 is completed as shown in FIG. 17,the optical fiber 11 is pressed by a force of several hundreds of gf inaccordance with the shrinkage of the sleeve 12 and moves to thefixed-side heater 93B; however, as one clamp 2A slidably moves in theforward movement direction, a tension that is applied to the opticalfiber 11 can be maintained constant such as several tens of gf.

Additionally, in the modified example, steps of driving and releasing ofthe openable-and-closable clamp of the paired right and left clamps 2Aand 2B and the openable-and-closable heater 93A, a cooling step afterheating, or the like are the same as the above, and are omitted here.

Other Modified Example

Hereinbelow, the other modified example of the embodiment will bedescribed.

Hereinbelow, explanation will be described below with reference to FIGS.4 to 17.

In the embodiment, in the aforementioned configuration shown in FIG. 6or the like, the pressing force with respect to the sleeve 12 which isdue to the two heaters 3A and 3B may be a pressing force exceeding atension under a rupture evaluation test of the spliced portion 11A atwhich the optical fiber 11 is fusion-spliced.

Here, a strength of the optical fiber fusion splicer portion under therupture evaluation test is generally approximately 200 gf whereas apressing force of the second force-applying member is approximately 500gf.

In the embodiment, since the constitution that can control theabove-described tension is provided, it is possible to cause thepressing force with respect to the sleeve 12 to exceed a break tensileof the spliced portion 11A of the optical fiber 11.

By means of this structure, it is possible to press the sleeve 12 by asufficient force.

Moreover, the rupture evaluation test of the spliced portion, which isdescribed in the invention and at which optical fibers arefusion-spliced, is a method of measuring a break tensile of the opticalfiber spliced portion, generally, is represented as a proof test force,and is used as a common indicator that represents connectivity of anoptical fiber fusion splicer.

For example, in a fusion splicer having a wide range proof test force,the tension thereof is in the range of 200 to 250 gf (refer to Internetwebsite;http://www.fujikura.co.jp/products/tele/o_f_splicers/td70005.html,http://www.fujikura.co.jp/products/data/FSM-100-J.pdf, or the like).

In addition, in the above-mentioned constitution of the embodiment, itis more preferable that the pressing faces of the two heaters 3A and 3Bwhich faces each other so as to sandwich the sleeve 12 be arranged in asubstantially vertical direction and the tensile strength member 13 bealways arranged in a substantially downward direction by utilizing theweight of the tensile strength member 13 that is inserted into thesleeve 12 from the point where the direction of the sleeve 12 can beconsistent such that the sleeve is in the position graphically shown in,for example, FIGS. 5 (a) and (b).

Particularly, “substantially vertical” means that it is substantiallyvertical to a horizontal plane.

The pressing face that is arranged in a substantially vertical directionmay be a surface that intersects with, for example, the horizontal planeby an angle of 90°±10°.

The pressing face may be a surface that intersects with, for example,the horizontal plane at an angle of 90°±30°.

In the embodiment, a backward movement stopper that restricts a movementof the clamp in the backward movement direction may be provided and thebackward movement stopper may be configured to be retractable.

As shown in FIGS. 14 to 17, a backward movement stopper 51 may be usedas the backward movement stopper.

A heater attachment base 31B shown in FIG. 14 views (a) and (b) has aback wall 31Bb that faces a back surface of the clamp 2A (fixed-side).

The back wall 31Bb is movable in a front-back direction with respect tothe other portion of the heater attachment base 31B.

The backward movement stopper 51 is provided on a front surface of theback wall 31Bb.

As shown in FIG. 14 view (a), firstly, before the optical fiber 11 isgrasped, one clamp 2A moves separately from the heater 3 by the firstforce-applying member 41 and comes into contact with the backwardmovement stopper 51, a movable range is ensured only in the forwardmovement direction.

In a state in which the paired right and left clamps 2A and 2B grasp theoptical fiber 11 and a tension is not applied to the optical fiber 11,immediately after the optical fiber 11 is grasped, or at the time ofstarting of pressing drive with respect to the sleeve 12 by the heater3, or before or after the time of the starting of the pressing drive,the backward movement stopper 51 is retracted.

In order to retract the backward movement stopper 51, the back wall 31Bbis only necessary to move in the backward movement direction (in adirection away from the clamp 2A).

Because of this, in a state in which a tension is applied to the opticalfiber 11, after the backward movable range in addition to the forwardmovable range of one clamp 2A is ensured, it is possible to press thesleeve 12 by the heater 3.

In other cases, a constitution that allows the backward movement stopperto retract is not limited to the example shown in the drawing.

For example, a constitution that allows the backward movement stopper 51to be removed from the other portion of the heater attachment base 31Bmay also be adopted.

In this case, the above retraction is possible by removing the backwardmovement stopper 51.

In the embodiment, a forward movement stopper that restricts a movementof the clamp 2A in the forward movement direction may be provided andthe forward movement stopper may be configured to be retractable.

In FIG. 14 view (a), reference numeral 52 represents the forwardmovement stopper.

The heater attachment base 31B shown in FIG. 14 views (a) and (c) has afront wall 31Bc on an attachment base 31Ba that faces a front surface ofthe clamp 2A (fixed side).

The front wall 31Bc is movable in a front-back direction with respect tothe other portion of the heater attachment base 31B.

The forward movement stopper 52 is provided on a back surface of thefront wall 31Bc.

Firstly, before the optical fiber 11 is grasped, from a state in whichone clamp 2A is separated from the heaters 3 by the first force-applyingmember 41 and is in contact with a backward movement stopper to a statein which the clamp moves forward until coming into contact with aforward movement stopper and is maintained, in a state in which thepaired right and left clamps 2A and 2B grasp the optical fiber 11 and atension is not applied to the optical fiber 11, immediately after theoptical fiber 11 is grasped, or at the time of starting of pressingdrive with respect to the sleeve 12 by the heaters 3, or before or afterthe time of the starting of the pressing drive, one clamp 2A is releasedfrom the contacting state with respect to the forward movement stopperand the forward movement stopper is retracted.

In the drawing shown as an example, in order to retract the forwardmovement stopper 52, the front wall 31Bc is only necessary to move inthe forward movement direction (in a direction away from the clamp 2A).

Because of this, it is possible to provide a structure in which, in astate in which a tension is applied to the optical fiber 11, after theforward movable range in addition to the backward movable range of oneclamp 2A is ensured, the sleeve 12 is pressed by the hater 3.

Additionally, the second cam mechanism 72 that is the same as the abovemay be used as the forward movement stopper, and a structure using thebackward movement stopper 51 that is shown in FIGS. 14 to 17 and isformed in the housing 5 may be adopted as the backward movement stopper.

Reference numeral 52 represents the forward movement stopper.

In the case of using a cam mechanism as the forward movement stopper, itis possible to retract the forward movement stopper by rotating the cammechanism.

Furthermore, a configuration that is removed from the other portion ofthe heater attachment base 31B may be adopted as the forward movementstopper 52.

In this case, the retraction is possible by removing the forwardmovement stopper 52.

Alternatively, a configuration described below may be adopted in theembodiment.

Firstly, before the optical fiber 11 is grasped, in a state in which anapplied force in a backward movement direction away from the heater 3 isapplied to one clamp 2A by the first force-applying member 41 and in astate in which one clamp 2A is stopped at the position away from an endof a movable range thereof by a third force-applying member (not shownin the figure) formed of an elastic member or a magnetic member which isused to allow one clamp 2A to move in a forward movement direction or athird force-applying member that allows one clamp 2A to move in aforward movement direction, in a state in which the paired right andleft clamps 2A and 2B grasp the optical fiber 11 and a tension is notapplied to the optical fiber 11, immediately after the optical fiber 11is grasped, or at the time of starting of pressing drive with respect tothe sleeve 12 by the heaters 3, or before or after the time of thestarting of the pressing drive, an applied force of one of the clamps inthe forward movement direction decreases by the third force-applyingmember, an applied force in the backward movement direction increases bythe first force-applying member, or the third force-applying member isretracted.

Consequently, in a state in which the paired right and left clamps 2Aand 2B apply a tension to the optical fiber 11, after the forwardmovable range Z in addition to the backward movable range K of one clamp2A is ensured, a constitution may be adopted which presses the sleeve 12by the heaters 3.

Here, as a method of controlling the applied force of the firstforce-applying member 41 or the third force-applying member that is notshown in the figure to be stronger or weaker, in the case of using amagnetic member in each force-applying member, for example, a method ofcontrolling a current value that is to be applied to an electromagnet ora method of moving the position of a permanent magnet.

In addition, in the case of using an elastic member in eachforce-applying member, for example, a method of moving one end of thespring serving as an elastic member is adopted.

For example, in a state in which one end of a spring is used as a fixedend, where the other end thereof is in contact with a clamp, and wherethe clamp is pressed by an elastic force of the compressed spring, as aresult of compressing the spring so that one end of the spring moves ina direction of approaching the other end thereof, it is possible toincrease the applied force.

Moreover, as a result of releasing the compression so that one end ofthe spring moves in a direction away from the other end thereof, it ispossible to weaken the applied force.

Alternatively, a configuration described below may be adopted in theembodiment.

Firstly, both the paired clamps 2A and 2B which are not particularlyshown in the figure are movable back and forth in the longitudinaldirection of the optical fiber 11, in a state in which one clamp 2Amoves separately from the heater 3 by the first force-applying member 41and comes into contact with the backward movement stopper (refer toreference numeral 51 show in FIG. 14 or the like) before the opticalfiber 11 is grasped, in a state in which a movable range is ensured onlyin the forward movement direction, and in a state in which the otherclamp 2B moves forward to the heater side 3 before the optical fiber 11is grasped, the paired right and left clamps 2A and 2B grasp the opticalfiber 11, and the optical fiber 11 is in a state in which a tension isnot applied thereto.

Thereafter, the other clamp 2B is started to move in the backwardmovement direction away from the heater side 3, one clamp 2A moves in aforward movement direction by the tension via the optical fiber 11, themovement of the other clamp 2B is stopped at the position away from theend of the movable range of one clamp 2A, therefore, in a state in whicha tension is applied to the optical fiber 11, after the forward movablerange Z in addition to the backward movable range K of one clamp 2A isensured, a constitution may be adopted in which the heater 3 presses thesleeve 12.

Alternatively, a configuration described below may be adopted in theembodiment.

Firstly, before the optical fiber 11 is grasped, in a state in which oneclamp 2A is separated from the heaters 3 by the first force-applyingmember 41 and is in contact with a backward movement stopper (refer toreference numeral 51 shown in FIG. 14 or the like) and a movable rangeis ensured only in the forward movement direction and in a state inwhich the paired right and left clamps 2A and 2B grasp the optical fiber11 and a tension is not applied to the optical fiber 11, the heaters 3press the sleeve 12 by a pressing force by the second force-applyingmember 42 which is greater than a tension that is to be applied to theoptical fiber 11 by the first force-applying member 41.

In addition, a configuration may also be adopted in which, as a resultof moving the optical fiber 11 in a pressing direction which is due tomovement of the sleeve 12 or deformation of the sleeve 12 after startingof the press, one clamp 2A is drawn to a forward movement direction by atension due to movement of the optical fiber 11, one clamp 2A isconfigured so as to be stopped at a position away from an end of amovable range, therefore, in a state in which a tension is applied tothe optical fiber 11 by the first force-applying member 41, a forwardmovable range Z is ensured in addition to a backward movable range K ofone clamp 2A, and thereafter, the heaters 3 heat the sleeve 12.

A configuration described below may be adopted in the embodiment.

Particularly, identical reference numerals are used for the elementswhich are described above, and the detailed explanations thereof areomitted here.

A reinforcing heating device shown in FIG. 34 is different from thereinforcing heating device shown in FIGS. 6 to 11 in that a cammechanism (the second cam mechanism 72) that restricts one clamp 2A frommoving in the backward movement direction is not present, in that aprotrusion 150 is formed at the openable-and-closable side 2Ab of theclamp 2A, and in that a control wall 151 is provided on the heaterattachment base 31B.

The protrusion 150 of the openable-and-closable side 2Ab includes: anextended portion 152 that extends from the rear edge of theopenable-and-closable side 2Ab toward the heater attachment base 31B;and an insertion protrusion 153 that protrudes rearward from the backsurface of the front end of the extended portion 152.

The upper face 153 a of the external surface of the insertion protrusion153 is an inclined surface that lowers as approaching the rear (the leftside in the drawing).

The control wall 151 is placed upright at the rear edge of the heaterattachment base 31B, and a receiving recess 155 that can receive theinsertion protrusion 153 is formed on the front surface 151 a thereof.

The upper face 155 a of the inner surface of the receiving recess 155 isan inclined surface that lowers as approaching the rear (the left sidein the drawing).

In an initial state of the control wall 151 (refer to FIG. 34), thefront surface 151 a is in contact with the insertion protrusion 153 andthereby restricts a backward movement of the clamp 2A.

The reinforcing heating device shown as this example is provided with aforce-applying mechanism 41 (first force-applying member) that applies atension to the optical fiber 11.

The force-applying mechanism 41 includes a forward force-applyingmechanism 41A and a rearward force-applying mechanism 41B.

The forward force-applying mechanism 41A includes force-applying members41 a and 41 b which are provided at a front-edge face of a fixed-side2Aa of the clamp 2A and the attachment base 31Ba of the heaterattachment base 31B, respectively.

The force-applying members 41 a and 41 b are magnetic members such as apermanent magnet or an electromagnet and have the same magnetic pole aseach other.

In the drawing shown as an example, both the force-applying members 41 aand 41 b have a north polarity.

The rearward force-applying mechanism 41B includes force-applyingmembers 41 c and 41 d which are provided at the rear-edge face of thefixed-side 2Aa of the clamp 2A and the back wall 31Bb of the heaterattachment base 31B, respectively.

The force-applying members 41 c and 41 d are magnetic members havingmagnetic poles different from each other.

In the drawing shown as an example, the force-applying member 41 c has anorth polarity and the force-applying member 41 d has a south polarity.

Due to the repulsive force between the force-applying members 41 a and41 b and the attractive force between the force-applying members 41 cand 41 d, a force is applied backward to the clamp 2A, and a tension isapplied to the optical fiber 11.

The protrusion 150 and the control wall 151 that includes the receivingrecess 155 and the front surface 151 a constitute a mechanism (a tensionmechanism or a tensile control device) that controls the pulling of theoptical fiber 11 (and the stopping thereof) by the force-applyingmechanism 41 based on an operation of grasping the optical fiber 11 bythe clamp 2A.

In the reinforcing heating device shown as this example, the motor 6controls the clamp 2A by the first cam mechanism 71 and by a force ofthe fifth force-applying member 45 and the tension mechanism iscontrolled by the operation of the clamp 2A.

As shown in FIG. 35, when the camshaft 7 rotates, theopenable-and-closable side 2Ab of the clamp 2A moves in a direction ofapproaching the fixed-side 2Aa thereof, and clamping bodies 2 b and 2 bgrasp the optical fiber 11.

As shown in FIG. 36, in accordance with the movement of theopenable-and-closable side 2Ab, the protrusion 150 lowers, the insertionprotrusion 153 reaches at the position at which is can enter thereceiving recess 155, therefore, the clamp 2A is in a state of capableof moving back and forth while the forward movable range Z in additionto the backward movable range K is ensured, and a tension is applied tothe optical fiber 11 by the force-applying mechanism 41.

As shown in FIG. 37, in accordance with the displacement of the thirdcam mechanism 73, the heater attachment base 31A approaches the heaterattachment base 31B, the sleeve 12 is sandwiched between the heaters 3Aand 3B, and the sleeve 12 is thereby heat-shrunk.

As shown in FIG. 38, the sleeve 12 and the optical fiber 11 move towardthe heater 3B in accordance with the shrinkage of the sleeve 12;however, since the clamp 2A slidably moves in the forward movementdirection (the right side in the drawing), a tension that is to beapplied to the optical fiber 11 is not in large excess.

As shown in FIG. 39, when the heater attachment base 31A moves in adirection away from the heater attachment base 31B by the third cammechanism 73, the sleeve 12 is released, the openable-and-closable side2Ab of the clamp 2A moves in a direction away from the fixed-side 2Aa bythe first cam mechanism 71, and gripping of the optical fiber 11 isreleased.

The protrusion 150 moves upward in accordance with the movement of theopenable-and-closable side 2Ab, and the insertion protrusion 153 returnsto the position at which the backward movement thereof is restricted bythe control wall 151.

At this time, in the insertion protrusion 153, since the upper face 153a moves upward along the inclination of the upper face 155 a of thereceiving recess 155, it is smoothly displaced from the receiving recess155.

In addition, not shown in FIGS. 6 to 11 or the like but as shown in FIG.34 or the like, the openable-and-closable side 2Ab is provided with aforce-applying member 2 a that presses the clamping body 2 b clampingthe optical fiber 11 in a direction to the clamping body 2 b of thefixed-side 2Aa.

A configuration described below may be adopted in the embodiment.

A reinforcing heating device shown in FIG. 40 is different from thereinforcing heating device shown in FIGS. 6 to 11 in that the second cammechanism 72 is not present, in that a force-applying mechanism 141(first force-applying member) is provided, and in that a protrusion 160that protrudes in a direction of approaching the heater attachment base31B is formed on the heater attachment base 31A.

The force-applying mechanism 141 is used to apply to a tension to theoptical fiber 11 and includes a forward force-applying mechanism 141Aand a rearward force-applying mechanism 141B.

The forward force-applying mechanism 141A includes force-applyingmembers 141 a and 141 b which are provided at the front-edge face of thefixed-side 2Aa of the clamp 2A and the attachment base 31Ba of theheater attachment base 31B, respectively.

The force-applying members 141 a and 141 b are magnetic members such asa permanent magnet or an electromagnet and have the same magnetic poleas each other.

In the drawing shown as an example, the force-applying members 141 a and141 b have a north polarity.

The rearward force-applying mechanism 141B includes force-applyingmembers 141 c and 141 d which are provided at the rear-edge face of thefixed-side 2Aa of the clamp 2A and the back wall 31Bb of the heaterattachment base 31B, respectively.

The force-applying members 141 c and 141 d are magnetic members havingthe same magnetic pole as each other.

In the drawing shown as an example, the force-applying members 141 c and141 d have a north polarity.

In an initial state shown in FIG. 40, the forward movable range Z andthe backward movable range K are ensured and the clamp 2A is in a stateof capable of moving back and forth; however, the clamp 2A stays at thisposition due to the repulsive force between the force-applying members141 a and 141 b and the repulsive force between the force-applyingmembers 141 c and 141 d.

A force-applying member 161 is provided at the front end of theprotrusion 160.

The force-applying member 161 is an magnetic member having the samemagnetic pole as that of the force-applying member 141 a.

In the drawing shown as an example, similar to the force-applying member141 a, the force-applying member 161 has a north polarity.

The protrusion 160 constitutes a mechanism (a tension mechanism or atensile control device) that controls increase and decrease in a degreeof the tension of the optical fiber 11 by the force-applying mechanism41 based on an operation of pressing the optical fiber 11 by the heater3A.

In the reinforcing heating device shown as this example, the motor 6controls the heater 3A by the third cam mechanism 73 and by a force ofthe second force-applying member 42, the tension mechanism is controlledby the operation of the heater 3A.

As shown in FIG. 41, when the openable-and-closable side 2Ab of theclamp 2A moves in a direction of approaching the fixed-side 2Aa inaccordance with rotation of the camshaft 7, the openable-and-closableside 2Ab and the fixed-side 2Aa grasp the optical fiber 11.

In the state shown in this drawing, since the heater attachment base 31Ais separated from the heater attachment base 31B, the force-applyingmember 161 of the protrusion 160 is located at the position away fromthe force-applying member 141 a of the clamp 2A.

In this state, a tension that is to be applied to the optical fiber 11is small.

As shown in FIG. 42, the heater attachment base 31A approaches theheater attachment base 31B in accordance with displacement of the thirdcam mechanism 73 which is due to rotation of the camshaft 7, theforce-applying member 161 of the protrusion 160 comes close to theforce-applying member 141 a of the clamp 2A.

Since the force-applying member 161 has the same magnetic pole as thatof the force-applying member 141 a, a repulsive force that is directedbackward (the left side in the drawing) is applied to the force-applyingmember 141 a.

Consequently, a tension that is applied to the optical fiber 11increases.

As shown in FIG. 43, the sleeve 12 is sandwiched between the heaters 3Aand 3B, and the sleeve 12 is heat-shrunk.

The sleeve 12 and the optical fiber 11 move toward the heater 3B inaccordance with the shrinkage of the sleeve 12; however, since the clamp2A slidably moves in the forward movement direction (the right side inthe drawing), a tension that is to be applied to the optical fiber 11 isnot in large excess.

As shown in FIG. 44, the heater attachment base 31A moves in a directionaway from the heater attachment base 31B by the third cam mechanism 73,the sleeve 12 is released, the openable-and-closable side 2Ab of theclamp 2A moves in a direction away from the fixed-side 2Aa by the firstcam mechanism 71, and gripping of the optical fiber 11 is released.

(Action and Effect)

According to the optical-fiber-spliced portion reinforcing heatingdevice 1 of the first embodiment of the invention described above, whenthe sleeve 12 is sandwiched between two heaters 3A and 3B and is heatshrunk, breaking of the optical fiber 11 or degradation in long-termreliability thereof is prevented by releasing an excessive tension thatis to be applied to the optical fiber 11, and a device is prevented frombeing larger in size.

Consequently, it is possible to heat-shrink the sleeve 12 in a shorteramount of time with a high level of reliability, and anoptical-fiber-spliced portion reinforcing heating device 1 having a highlevel of handleability can be realized.

Second Embodiment

Hereinbelow, a second embodiment of the invention will be described withreference to an example shown in each drawing.

Particularly, the embodiment will be partially described with referenceto the same drawings shown in the aforementioned first embodiment,identical reference numerals are used for the common elements which aredescribed above, for example, the paired right and left clamps 2A and2B, two heaters 3A and 3B, or the like, and the detailed explanationsthereof are omitted here.

In the embodiment, as shown in FIG. 4 (also refer to FIG. 6), the pairof right and left clamps 2 (2A, 2B) which grasp the optical fiber 11 andare the same as in the case of the first embodiment, two heaters 3 (3A,3B) which press and heat the sleeve 12 that covers the coating-removedportion of the optical fiber 11, and the second force-applying member 42that applies a pressing force to at least one or more of the two heaters3A and 3B by use of one of an elastic member and a magnetic member withthe sleeve 12 interposed therebetween in accordance with control of themotor 6 where the heaters are arranged opposite to each other with thesleeve 12 interposed therebetween are provided.

Specifically, in addition to the above-description, the reinforcingheating device 1 according to the embodiment is characterized toinclude: a first operation member 81 (a mechanism that operates tosandwich an optical fiber) that operates the first cam mechanism 71rotationally driven by the motor 6 so as to operate the fifthforce-applying member 45 (refer to FIG. 29) that is to be displaced inaccordance with a motion of the first cam mechanism 71 and is formed ofan elastic member or a magnetic member and so that the fifthforce-applying member presses the optical fiber 11 in the direction inwhich the paired right and left clamps 2A and 2B sandwich and grasp theoptical fiber by the displacement; and a third operation member 83 (amechanism that operates to sandwich a sleeve) that operates the thirdcam mechanism 73 that is provided on the camshaft 7 on the same axis asthat of the first cam mechanism 71 and is rotationally driven by controlof the same motor 6 so as to operate the second force-applying member 42that is to be displaced in accordance with a motion of the third cammechanism 73 and so that the second force-applying member presses thesleeve 12 in the direction in which two heaters 3A and 3B sandwich andpress by the displacement.

Furthermore, in the second embodiment, an example is adopted which issimilar to the above-mentioned first embodiment and which includes: thefirst force-applying member 41 that presses at least one of the clamps 2in the direction in which a tension is applied to the optical fiber 11;and a second operation member 82 that operates the second cam mechanism72 that is provided on the camshaft 7 on the same axis as that of thefirst cam mechanism 71 and is rotationally driven by the motor 6 so asto operate a first force-applying member 71 that is to be displaced inaccordance with a motion of the second cam mechanism 72 and so that thefirst force-applying member applies a tension to the optical fiber 11 bythe displacement.

Additionally, similar to the first embodiment, the second embodimentwill be described with reference to a constitution as an example inwhich the pressing force with respect to the sleeve 12 by the secondforce-applying member 42 is greater than the tension to the opticalfiber 11 by the first force-applying member 41; in a state in which atension is applied to the optical fiber 11 by the first force-applyingmember 41, the backward movable range K in a direction away from theheaters 3 in the longitudinal direction of the optical fiber 11 isensured and the forward movable range Z in which one clamp 2A thatapplies a tension can move to the heater side 3 is ensured; and theclamp 2A moves in the direction in which the tension that is to beapplied to the optical fiber 11 as a result of pressing the sleeve 12 bythe heaters 3 and by the second force-applying member 42 is diminished.

Moreover, in the embodiment, each operation member (each operationmechanism) which will be described later in addition to theabove-described first operation member 81 or the third operation member83 will be explained with reference to an example configuration having alever-shaped member.

Furthermore, in the explanation described below, a reinforcing heatingdevice according to the second embodiment will be mainly explained inthat it is different from the case of the aforementioned firstembodiment.

(Camshaft and Each Cam Mechanism)

The reinforcing heating device 1 according to the embodiment isdifferent from the above-mentioned first embodiment in that cammechanisms, each of which will be particularly described later, areprovided on the camshaft 7 rotationally driven by the motor 6 and inthat each of operations of opening and closing the openable-and-closableside of the paired right and left clamps 2A and 2B, operations ofopening and closing one heater 3A, a slide movement of one clamp 2A inthe longitudinal direction of the optical fiber 11 (a direction in whicha tension is adjusted), and operations of opening and closing the lid 10is driven and carried out by a corresponding force-applying member byuse of the operation member that is displaced in accordance with amotion of the above cam mechanism.

Hereinbelow, cam mechanisms which are adopted in the reinforcing heatingdevice according to the embodiment will be described with reference to abreakaway view shown in FIG. 4, a front view shown in FIG. 23, and FIG.24 views (a) and (b) to FIG. 28 views (a) and (b).

As shown in FIG. 4, four types and seven cam mechanisms are mounted onone camshaft 7 and are arranged in order from the left side in thedrawing as follows.

Particularly, in the configuration shown in the drawing as an example,an auxiliary movement lever which will be described later is notprovided, and a drive torque inversion mechanism is not provided isshown.

(1) fourth cam mechanism 74 (opening and closing the lid 10)(2) first cam mechanism 71 (opening and closing the one clamp 2A)(3) second cam mechanism 72 (backward movement stopper used to apply atension of one clamp 2A)(4) third cam mechanism 73 (opening and closing one heater 3A)(5) third cam mechanism 73 (opening and closing one heater 3A)(6) first cam mechanism 71 (opening and closing the other clamp 2B)(7) fourth cam mechanism 74 (opening and closing the lid 10)

Here, each cam mechanism that is provided on the camshaft 7 of thereinforcing heating device 1 which is described in the embodiment is notlimited to a rotation cam-shaped configuration formed shown as anexample in the drawing and may include, for example, a so-calledspiral-shaped configuration having a contact face that varies in thelongitudinal direction of the camshaft.

Furthermore, the cam mechanism which is described in the invention isnot limited to a mechanism shown as an example in the drawing and mayinclude, for example, a structure in which a rotation lever-shapedmember is provided on the camshaft.

Moreover, in a configuration of the embodiment, rotation of the motor 6serving as a drive source is transmitted through a gear wheel mechanism61 to the camshaft 7 and each cam mechanism.

(Two Heaters)

In the embodiment, similar to the first embodiment, it is only necessarythat one of two heaters 3A and 3B is configured to be driven by themotor 6 so as to be openable and closable.

As long as the two heaters 3A and 3B are configured such that onethereof is movable and driven and the other thereof is fixed, themovable mechanism of the heater, or an elastic member or a magneticmember which presses the heater can be provided only on one of theheaters, and therefore, the device can be reduced in size.

Particularly, the other heater 3B (fixed-side) shown in FIG. 6 or thelike is not shown in a breakaway view of FIG. 4, and one heater 3Aserving as an openable-and-closable side is only shown therein. It isonly necessary that, the back side or the front side in FIG. 4 isadequately selected and the positional relationship between the twoheaters 3A and 3B is adopted in the selected side.

(Pair of Right and Left Clamps)

FIGS. 29 and 30 are partial breakaway views particularly showing oneclamp 2A of the reinforcing heating device 1 shown in FIG. 4 and asurround mechanism thereof.

As shown in FIG. 29, the openable-and-closable side of one clamp 2A isattached to the first operation member 81 and the openable and closablefixed-side thereof is attached to the second operation member 82 servingas a clamp attachment base.

Moreover, the first operation member 81 carries out operations ofopening and closing one clamp 2A around a rotation support 81 a.

The first operation member 81 is driven by the first cam mechanism 71and carries out operations of opening and closing one clamp 2A as aresult of being pressed by the fifth force-applying member 45 formed bya torsion coil spring.

In addition, a grasping rubber 2 b used to directly grasp the opticalfiber 11 is provided on one clamp 2A and is also similarly applied tothe other clamp 2B which is not shown in FIG. 29.

Furthermore, as shown in FIGS. 29 and 30, the paired right and leftclamps 2A and 2B are configured to slidably move in the longitudinaldirection of the optical fiber 11 around a slide support 82 a.

Also, the first force-applying member 41 which is used to allow thepaired right and left clamps 2A and 2B to move in the backward movementdirection so as to apply a tension to the optical fiber 11 and which isformed of a compression coil spring (elastic member) is provided topress the second operation member 82 (and the first operation member81).

Additionally, the backward movement stopper 51, that restricts amovement of the paired right and left clamps 2A and 2B in the backwardmovement direction thereof when the optical fiber 11 is grasped by thepaired right and left clamps 2A and 2B, is provided at the firstoperation member 81.

When the optical fiber 11 is grasped by the operations of opening andclosing the paired right and left clamps 2A and 2B, the backwardmovement stopper 51 restricts the movement of the paired right and leftclamps 2A and 2B in the backward movement direction thereof by being incontact with the second cam mechanism 72 provided on the camshaft 7.

Consequently, in the constitution, after the optical fiber 11 isgrasped, the contacting state between the second cam mechanism 72 andthe backward movement stopper 51 is released, it is possible to apply atension to the optical fiber 11 by the first force-applying member 41 asa result of releasing the paired right and left clamps 2A and 2B to bemovable in the backward movement direction thereof.

(Other Configuration of Each Element and Operation Mode)

In the embodiment, as shown in FIG. 18 as an example, the thirdoperation member 83 can be configured to function as a heater attachmentbase on which the openable and closable heater 3A is provided and to bedriven to rotate around the rotation support 83 a.

In the first embodiment, the heater attachment base which is describedwith reference to FIG. 6 or the like uses a slide movable system.However, balance of the first point of action at which the heater 3presses the sleeve 12, the second point of action at which the heater 3A(heater attachment base) presses a driving body (third cam mechanism),and the point of effort at which the second force-applying member 42presses the heater 3A (heater attachment base) varies with conditions.

Because of this, a force is easy to work in a direction (torsion) inwhich the heater attachment base is inclined in the slide movablesystem. If a slide guide mechanism having a resistance to torsion or amember such as a linear bearing is not provided on a heater movablemechanism, the movement of the heater attachment base does not becomesmooth. In the case of using the above-described mechanism or themember, there is a problem in that the reinforcing heating devicebecomes larger in size.

In the embodiment, as a result of configuring the third operation member83, on which one heater 3A is provided, by the lever-shaped member thatis driven to rotate around the rotation support 83 a, it is possible toreduce the entire device in size.

In the embodiment, for example, as shown in FIG. 4, FIG. 24 views (a)and (b) to FIG. 28 views (a) and (b) or the like which will be describedlater, at least any of operation members can be configured by alever-shaped member that rotationally moves around each of the rotationsupports parallel to the optical fiber 11 and the rotation shafts of thesleeve 12, and each cam mechanism (the camshaft 7), and it is preferablein that the aforementioned effect is easily obtained.

In the examples shown in FIG. 24 views (a) and (b) to FIG. 28 views (a)and (b), the first, the third, and the fourth operation members 81, 83,and 84 are configured by the lever-shaped member that rotationally movesaround the rotation supports parallel to the rotation shafts of thefirst, the third, and the fourth cam mechanisms 71, 73, and 74,respectively.

Furthermore, as shown in FIG. 4 as an example, it is preferable that thecamshaft 7 be configured to be arranged among each rotation support thatis mentioned that is disposed and is disposed under the device, thepaired right and left clamps 2A and 2B that are disposed above thedevice, the two heaters 3A and 3B, and the lid 10 in that it is possibleto further reduce the entire device in size.

In addition, the second force-applying member 42 that is used to pressone heater 3A can be configured by a coil spring that is provided on therotation support 83 a of the third operation member 83 which serves as aheater attachment base shown in FIG. 18.

The third operation member 83 according to the embodiment is pressed bythe second force-applying member 42 formed of an elastic member or amagnetic member; however, in order to obtain a state in which avariation in a pressing force depending on the third operation member 83is low, a compression coil spring having an overall length longer thanthe movable stroke as described above is necessary.

However, in the case of using a compression coil spring having a longoverall length, there is a problem in that the entire device becomeslarger in size.

In contrast, as a result of providing the second force-applying member42 formed of a coil spring on the rotation support 83 a as describedabove and utilizing a rotational operation around the rotation support83 a, it is possible to obtain a constant pressing force in a widemovable range, and it is possible to reduce a reinforcing heating devicein size.

Additionally, in the embodiment, it is preferable that a coil spring beused as the second force-applying member 42 pressing two heater units 3Aand 3B, the mechanism grasping the optical fiber 11 in the paired rightand left clamps 2A and 2B, and the force-applying member of the lid 10(not shown in the figure) as described above and that theabove-mentioned rotation support be on the same axis as that of the coilspring in that it is possible to further reduce the entire device insize.

Moreover, similar to the above-mentioned first embodiment, one clamp 2Amay also be driven by the same mechanism as in the case of theabove-described one heater 3A.

That is, in the configuration as shown in FIG. 4, by use of the firstcam mechanism 71 in accordance with the rotational drive of the camshaft7 by the motor 6, the fifth force-applying member 45 formed of anelastic member or a magnetic member (refer to FIG. 29) can be operatedto press the optical fiber in the direction in which the paired rightand left clamps 2A and 2B sandwich and grasp the optical fiber 11 viathe first operation member 81.

As a result of allowing the openable-and-closable side of the pairedright and left clamps 2A and 2B to move by use of the motor 6 serving asa power source as mentioned above, effects as described below can beobtained.

(1) Since the operations of opening and closing that were conventionallyand manually carried out by an operator are automatically carried out,it is possible to speed up an operation of heat shrinking the sleeve 12using the reinforcing heating device.(2) Since it is not necessary for an operator to operate a clamp withtheir finger, it is not necessary to design a clamp to be a shapesuitable for opening and closing the clamp with human finger.

Conventionally, for example, protrusions which are not shown in thefigure and easily allow finger to pick them are provided on clamps thatare disposed at respective right and left sides in the longitudinaldirection of the optical fiber, and a space for finger is provided closethereto. Therefore, the

clamp was larger in size and the configuration thereof was complicated.

According to the embodiment, as a result of automating the operations ofgrasping, opening, and closing the paired right and left clamps 2A and2B, it is possible to reduce each clamp in size.

(3) In order to carry out the operation using the reinforcing heatingdevice, it is necessary to perform operations in the sequence such thatthe clamp is closed after setting the optical fiber, a tension isapplied to the optical fiber, the forward movable range and the backwardmovable range are ensured, and the heat shrinkage is carried out bypressing the heaters.

However, there is a possibility that an operator having a low level ofproficiency causes error in operation.

As described in the embodiment, as a result of automating the pressingoperation of one heater 3A and the operations of grasping, opening, andclosing the paired right and left clamps 2A and 2B, it is possible toprevent such error in operation.

Furthermore, as described in detail in the embodiment, at least any twoor more of the cam mechanisms that are provided on the same axis as thatof the camshaft 7 and are rotationally driven, particularly, the firstcam mechanism 71 and the third cam mechanism 73 are preferablyconfigured so that a rotating drive force by the motor 6 is reduced bydetermining a timing of combining a positive driving that needs a drivetorque and a negative driving that receives a torque.

As described above, several hundreds of gf is required as a pressingforce for pressing one heater 3A and a pressing force of severalhundreds of gf is also required to grasp the optical fiber 11 by drivingthe openable-and-closable side of the paired right and left clamps 2Aand 2B.

In the case where, for example, the peaks of the above driving andpressing timings (peak of the pressing force) overlap, a force of acompression coil spring such as represented by the following formula(heater of 500 gf+one of the clamps of 250 gf+the other of the clamps of250 gf=1000 gf) works.

Furthermore, as mentioned above, in a case of driving each operationmember by the rotary motion around each rotation support, the requireddriving power further increases.

In addition, in the case where, for example, a distance from eachrotation support to a compression coil spring forming eachforce-applying member is twice the distance from the rotation support toeach cam mechanism, it is necessary for a force of each cam mechanism tobe twice the force of the compression coil spring under the principle ofleverage.

As a result, the total of the force to drive the camshaft increases tobe 2000 gf, and there is a problem in that the drive mechanism thereforbecomes larger in size.

In the embodiment, FIGS. 19 and 20 are timing charts (graph) that showstimings of operating the first cam mechanism 71 that grasps and drivesthe openable-and-closable side of the paired right and left clamps 2Aand 2B and the third cam mechanism 73 that drives one heater 3A, and thecharts describe an action and an effect which compensate a positivedriving and a negative driving.

In FIGS. 19 and 20, the x-axis represents an angle of each cam mechanismand the y-axis represents an amount of extrusion in the direction ofeach force-applying member (compression coil spring) from the rotationalcenter of each cam mechanism.

This means that, FIGS. 19 and 20 graphically illustrates the case where,for example, each operation member carries out the above-mentionedrotary motion around each rotation support.

As shown in FIG. 19, in the case where the rotation of the first cammechanism that drives the clamps is in the range of 0 to 90°, an amountof extrusion of the cam mechanism decreases.

Such operation means the process in which the clamps are closed and thegrasping operation is carried out.

In this section, a driving power is not necessary for the cam mechanism,rather than, the force-applying member formed of a compression coilspring facilitates the rotation of the cam mechanism.

In this case, the force by which the compression coil spring facilitatesthe rotation of the cam mechanism is 500 gf that is twice the clampingforce of 250 gf (the principle of leverage).

When the clamps are closed and thereby grasp the optical fiber, next,one of the heaters is closed.

In the chart shown in FIG. 19, the section in which the rotation of thesecond cam mechanism allowing one of the heaters to be driven is 90 to180° represents the operation.

Thereafter, the second cam mechanism is stopped at the second positionof 180°, and heating with respect to the sleeve by two heaters isstarted.

When shrinkage of the sleeve is completed, the heating is stopped.

Subsequently, in the range of 180 to 360° of the chart shown in FIG. 19,one of the heaters and the openable-and-closable side of the pairedright and left clamps are simultaneously carry out a release operation;however, a driving power of 2000 gf is required for the camshaft.

Additionally, an open operation is slowly carried out in considerationof reduction in the load to the drive mechanism in the reinforcingheating device; however, if the operation is excessively slow, there areproblems in that the sleeve (optical fiber) cannot be removed from thereinforcing heating device and time for removal thereof becomes longer.

The chart shown in FIG. 20 illustrates that a timing (driving power) inthe configuration in which the driving power of the heater is invertedin order to reduce an excessive driving power as shown in FIG. 19.

As shown in FIG. 20, in the range of 180 to 360° which is theproblematic section in FIG. 19, the total driving powers of one heater3A (third cam mechanism 73) and the openable-and-closable side of thepaired right and left clamps 2A and 2B are cancelled each other, atorque is not necessary at least under the theoretical concept(practically, the drive torque is not zero due to a friction betweenmembers or the like).

As a result of adopting the constitution that allows the torques of themechanisms to be cancelled and to compensate each other by partiallyinverting them as described above, it is possible to reduce the drivemechanism in size while reducing the drive torque, and therefore, it ispossible to reduce a reinforcing heating device in size.

Moreover, as shown in FIGS. 21 and 22 as an example in the embodiment, aconstitution that uses an auxiliary movable lever may be adopted inorder to invert the drive torque.

Particularly, for example, each operation member that carries out therotary motion around the rotation support as mentioned above will bedescribed below; however, it is not limited to this, it may be appliedto a slide drive system.

Hereinafter, a configuration shown in FIG. 21 will be described.

(1) A compression coil spring 83D that is in a state of being compressedis inserted between the third operation member 83 serving as a heaterattachment base and an auxiliary movement lever 83C.

The compression coil spring 83D creates a force so as to separate thethird operation member 83 from the auxiliary movement lever 83C;however, since a contact portion 83 b functions as a stopper, they areconfigured not to be separated from each other over a set distance bythe contact.

(2) That is, the third operation member 83 and the auxiliary movementlever 83C are configured to coordinately move.(3) Particularly, two springs serving as the compression coil spring 83Dand an auxiliary compression coil spring 83E are provided in the drawingshown as an example. The spring force of the auxiliary compression coilspring 83E is sufficiently weaker than that of the compression coilspring 83D and only functions to press the auxiliary movement lever 83Conto the third cam mechanism 73.(4) When the auxiliary movement lever 83C is driven by the third cammechanism 73, the third operation member 83 serving as a heaterattachment base is coordinately driven.(5) On the other hand, after the two heaters 3A and 3B comes intocontact with the sleeve 12, the third operation member 83 cannot moveany more.

As a result, the third operation member 83 produces an action ofcontracting the compression coil spring 83D, the force of the spring atthis time creates the pressing force with respect to the sleeve 12.

According to the above-described operation, when the operation ofclosing one heater 3A is carried out, a drive torque used to press themis necessary. When one heater 3A is opened, since the drive torque isnot necessary (released), it is possible to create a drive torque thatis opposite to the paired right and left clamps 2A and 2B.

More specifically, in the embodiment, in the constitution including eachcam mechanism as shown in FIG. 4, in at least any of the cam mechanisms,particularly, in the first cam mechanism 71 and the third cam mechanism73, the configuration shown in a schematic view (diagram) of FIG. 21 maybe applied to each of the first operation member 81 and the thirdoperation member 83.

That is, a configuration can be adopted in which an auxiliary movablemember (refer to reference numeral 83C in FIG. 21) is disposed on theopposite side of the first operation member 81 and the third operationmember 83 with the camshaft 7 interposed therebetween, each operationmember is coupled to the auxiliary movable member via an elastic memberor a magnetic member, a positive driving of the rotary drive torque ofeach cam mechanism is inverted to a negative driving as a result ofdisplacing the auxiliary movable member instead of each operation memberin accordance with a motion of each cam mechanism, and therefore, thepositive driving and the negative driving are combined and therebydiminished between the first cam mechanism 71 and the third cammechanism 73.

Because of this, there is no need to increase the driving force of themotor 6, and it is possible to reduce the entire device in size.

Additionally, for example, as shown in FIG. 22, even in the case ofusing tension coil springs 83F and 83G as each coil spring, the sameeffect as the aforementioned effect is obtained, and it is possible tofurther reduce the reinforcing heating device in size.

Moreover, in the embodiment, as also described in the first embodiment,it is preferable that a cam mechanism be used to drive one heater 3Aserving as an openable-and-closable side and that a structure be drivenby the third cam mechanism 73 as shown in FIG. 4, 6, or the like.

Furthermore, in this configuration, it is possible to further reduce theentire device in size by arranging the third cam mechanism 73 at theposition between the rotation support and one heater 3A.

In addition, in the embodiment, similar to the case of theaforementioned one heater 3A, a configuration may be adopted whichallows the openable-and-closable side of the paired right and leftclamps 2A and 2B to be driven to rotate around the rotation support.

In the first embodiment, the paired right and left clamps 2A and 2Bwhich are described with reference to FIG. 6 or the like uses a slidemovable system. However, balance of the first point of action at whichthe clamps 2 presses the optical fiber 11, the second point of action atwhich the clamps 2 presses the driving body (the first cam mechanism71), and the point of effort at which the fifth force-applying member(refer to reference numeral 45 in FIG. 29) presses the clamps varieswith conditions.

Because of this, a force is easy to work in a direction (torsion) inwhich the clamp attachment base is inclined. If a slide guide functionhaving a resistance to torsion or a member such as a linear bearing isnot provided on a clamp movable mechanism, the movement of theattachment base does not become smooth. In the case of using theabove-described mechanism or the member, there is a problem in that thereinforcing heating device becomes larger in size.

In the embodiment, as a result of configuring the openable-and-closableside of the paired right and left clamps 2A and 2B by a lever-shapedmember that rotationally moves around the rotation support, it ispossible to reduce the entire device in size.

Moreover, in the embodiment, as also described in the first embodiment,it is preferable that a cam mechanism be used to drive theopenable-and-closable side of the paired right and left clamps 2A and 2Band that a structure be driven by the first cam mechanism 71 as shown inFIG. 4, 29, or the like.

Furthermore, in this configuration, it is possible to further reduce theentire device in size by arranging the first cam mechanism 71 at theposition between the rotation support and the paired right and leftclamps 2A and 2B.

Additionally, as shown in FIG. 29, the fifth force-applying member 45that is used to grasp the optical fiber 11 by use of the paired rightand left clamps 2A and 2B may also be configured by an elastic membersuch as a coil spring that is provided at the rotation support 81 a ofthe first operation member 81 serving as a clamp attachment base.

The first operation member 81 (clamp attachment base) to which theopenable-and-closable side of the paired right and left clamps 2A and 2Bis attached as shown in FIG. 4 or 29 is pressed by the fifthforce-applying member 45 formed of an elastic member or a magneticmember; however, in order to obtain a state in which a variation in apressing force depending on the first operation member 81 serving as aclamp attachment base is low, a compression coil spring having anoverall length longer than the movable stroke as described above isnecessary.

However, in the case of using a compression coil spring having a longoverall length, there is a problem in that the entire device becomeslarger in size.

In contrast, as a result of providing the fifth force-applying member 45formed of a coil spring on the rotation support 81 a as described aboveand utilizing a rotational operation around the rotation support 81 a,it is possible to obtain a constant pressing force in a wide movablerange, and it is possible to reduce a reinforcing heating device insize.

Also, in the embodiment, a structure can be adopted which allows theopenable-and-closable side of the paired right and left clamps 2A and 2Band one heater 3A to be driven by the motor 6 that is the same drivesource.

As mentioned above, as each clamp which is the openable-and-closableside is operated by utilizing the motor 6 that serves as a drive sourcecommon to one heater 3A, one drive source mounted thereon as a device isonly required, and therefore, it is possible to reduce a reinforcingheating device in size.

Furthermore, in the embodiment, a structure can be adopted in which, asa result of driving the first to third cam mechanisms 71, 72, and 73 bythe motor 6 serving as the same drive source, one clamp 2A is operatedto apply a tension to the optical fiber 11.

Moreover, in the embodiment, as shown in FIG. 4 as an example, astructure can be adopted which allows the openable-and-closable side ofthe paired right and left clamps 2A and 2B and one heater 3A to bedriven by the respective cam mechanisms that are provided on the commoncamshaft 7 and on the same axis.

In such case, as shown as an example in the drawing, as a result ofarranging two first cam mechanisms 71 that are used to drive theopenable-and-closable side of the paired right and left clamps 2A and 2Band two third cam mechanisms 73 that are used to drive one heater 3A onone camshaft 7, effects as described below can be obtained.

(1) Since one camshaft can drives all of movable bodies, a drivingmember that is disposed inside each drive unit or a connection memberthat links the driving members of the units is not necessary.

Accordingly, it is possible to reduce a reinforcing heating device insize.

(2) As a result of varying the phases of the cam mechanisms, it ispossible to control the sequence of opening and closing the clamp by useof slight one member.

Accordingly, it is possible to reduce a reinforcing heating device insize.

Additionally, in the embodiment, the forward movement stopper or thebackward movement stopper of one clamp 2A can be driven by the motor 6serving as a drive source.

As described above, as a result of allowing at least one of the pairedright and left clamps 2A and 2B to be movable in the longitudinaldirection of the optical fiber 11 and as a result of driving the secondcam mechanism 72 serving as a backward movement stopper via the camshaft7 by the motor 6, effects as described below can be obtained.

(1) Since it is not necessary for an operator to operate the forwardmovement stopper or the backward movement stopper to be retracted withtheir finger, it is not necessary to design them to be a shape suitablefor opening and closing them with human finger.

That is, since the retraction mechanism can be accommodated in thedevice without necessary to expose it to the surface thereof, it ispossible to reduce a reinforcing heating device in size.

(2) In order to carry out the operation using the reinforcing heatingdevice, it is necessary to perform operations in the sequence such thatthe clamp is closed after setting the optical fiber, a tension isapplied to the optical fiber, the forward movable range and the backwardmovable range are ensured, and the heat shrinkage is carried out bypressing the heaters.

However, there is a possibility that an operator having a low level ofproficiency causes error in operation.

As described in the embodiment, as a result of automating the operationof retracting the forward movement stopper or the backward movementstopper, it is possible to prevent such error in operation.

Furthermore, in the embodiment, in addition to the openable-and-closableside of the above-mentioned paired right and left clamps 2A and 2B andone heater 3A, the second cam mechanism 72 serving as the aforementionedbackward movement stopper or a forward movement stopper which is notshown in the figure may be configured to be movable by the motor 6 thatis the same drive source.

As stated above, as each clamp is operated by utilizing theopenable-and-closable side of the paired right and left clamps 2A and 2Bor the motor 6 that serves as a drive source common to one heater 3A,one drive source mounted thereon as a device is only required, andtherefore, it is possible to reduce a reinforcing heating device insize.

Moreover, as shown in FIG. 4 as an example, a structure can be adoptedwhich allows the openable-and-closable side of the paired right and leftclamps 2A and 2B, one heater 3A, and each stopper to be driven by therespective cam mechanisms that are provided on the common camshaft 7 andon the same axis.

In the drawing shown as an example, as a result of arranging two firstcam mechanisms 71 that are used to drive the openable-and-closable sideof the paired right and left clamps 2A and 2B, two third cam mechanisms73 that are used to drive one heater 3A, and the second cam mechanism 72serving as a backward movement stopper on one camshaft 7, effects asdescribed below can be obtained.

(1) Since one camshaft can drives all of movable bodies, a drivingmember that is disposed inside each drive unit or a connection memberthat links the driving members of the units is not necessary.

Accordingly, it is possible to reduce a reinforcing heating device insize.

(2) As a result of varying the phases of the cam mechanisms, it ispossible to control the sequence of opening and closing the clamp by useof slight one member.

Accordingly, it is possible to reduce a reinforcing heating device insize.

As remarked above, according to the reinforcing heating device of theembodiment, since it is only necessary that one camshaft 7 that isproperly adjusted to the reinforcing heating device is designed,improvements in reduction in the reinforcing heating device in size canbe achieved, it is possible to reduce the size of the reinforcingheating device.

Furthermore, in the embodiment, a constitution may also be adopted whichincludes: the lid 10 that is used to open and close the reinforcingheating device; the sixth force-applying member 46 that applies a forceof closing the lid 10 by use of one of an elastic member and a magneticmember thereto; the fourth cam mechanism 74 that is provided on thecamshaft 7 on the same axis as those of the first to third cammechanisms 71 to 73 or is disposed on the other camshaft (not shown inthe figure) parallel to the camshaft 7; and a fourth operation member 84that serves as a mechanism operating the applied force of the sixthforce-applying member 46 to close the lid 10 in accordance with thedisplacement of the fourth cam mechanism 74.

Consequently, the same motor 6 can be configured to allow theaforementioned each force-applying member to operate the paired clamps2A and 2B, the heater 3, and the lid 10 by the first to fourth cammechanisms 71 to 74.

In this case, a configuration may also be adopted which carries outoperations of opening and closing the lid 10 by displacing the fourthcam mechanism 74 with respect to the fourth operation member 84 via anelastic member such as a spring, a rubber, or a sponge, or a magneticmember such as a permanent magnet, or an electromagnet.

The effect described below is obtained by adopting the above-describedconfiguration.

(1) Even in the case where the reinforcing heating device is not in usefor a predetermined time, as a result of closing the lid, there is nopossibility that rain water or the like does not enter the inside of thedevice.(2) Even in the case where the reinforcing heating device is not in usefor a predetermined time, as a result of closing the lid, there is nopossibility that dust, powder or the like do not enter the inside of thedevice.(3) As the lid is closed with the start of the heating, it is possibleto prevent an operator finger from being erroneously in contact with theinner heater and from being burn.

Particularly, the above-described the lid 10 is preferably made of atransparent material so that it is possible to visually check a progressof shrinkage of the sleeve 12 during heating.

Moreover, different from the case of the camshaft 7, it is not necessaryfor the rotation support axis of each operation member in theabove-description to be common (on the same axis) to all operationmembers.

Furthermore, it is not necessary for all operation members torotationally move around the rotation support, and one of them isadequately selected and can be operated.

Additionally, in the embodiment, the paired right and left clamps 2A and2B, the aforementioned one heater 3A, the backward movement stopper orthe forward movement stopper, the lid 10, or the like can be driven byuse of the motor 6 as a common drive source and by the respective cammechanisms that is provided on one camshaft 7.

That is, the configuration can be adopted in which, the paired right andleft clamps 2A and 2B is driven by the motor 6 serving as a common drivesource so as to grasp the optical fiber 11, one clamp 2A is driven so asto apply a tension to the optical fiber 11, furthermore, one heater 3Ais driven so as to sandwich and press the sleeve 12, and additionally,the operations of opening and closing the lid 10 are carried out.

As mentioned above, as a result of causing one motor 6 to carry out allfunctions, it is possible to reduce the entire reinforcing heatingdevice in size.

In addition, as the above-mentioned mechanism is driving by one camshaft7, a driving member that is disposed inside each drive mechanism or aconnection member that links the mechanisms is not necessary, andtherefore, it is possible to reduce the entire device in size.

Furthermore, as shown in FIG. 28 views (a) and (b), a semidisc 91A and aphoto sensor 91B that are used to detect a rotational position of thecamshaft 7 is provided near the third cam mechanism 73.

Moreover, in the example shown in FIG. 4, all operation members areconfigured of a lever-shaped member that is driven to rotate around eachrotation support.

Moreover, a torsion coil spring is used as an elastic member 46 that isused to open and close the lid 10 or the fifth force-applying member 45(refer to FIG. 29) that is used to open and close the paired right andleft clamps 2A and 2B, a double torsion spring is used as the secondforce-applying member 42 that is used to open and close one heater 3A,and additionally, a compression coil spring is used as the firstforce-applying member 41 that applies a tension to the optical fiber 11of one clamp 2A in the longitudinal direction thereof.

Here, FIG. 23 is a front view showing the reinforcing heating device 1according to the embodiment, cross-section lines A-A to E-E shown inFIG. 23 shows cross-sectional positions of cross-sectional views shownin FIG. 24 views (a) and (b) to FIG. 28 views (a) and (b), respectively.

Consequently, FIG. 24 to FIG. 28 shows states in which each operation iscarried out at the position of each portion described below.

(1) A-A (FIG. 24 views (a) and (b)): operation of opening and closingone heater 3A by use of the third cam mechanism 73.(2) B-B (FIG. 25 views (a) and (b)): operation of opening and closingone clamp 2A by use of the first cam mechanism 71.

Since one clamp 2A is configured to be able to slide in the longitudinaldirection of the optical fiber 11, the position of the rotation support81 a is at a high level in the example shown in FIG. 25 views (a) and(b).

(3) C-C (FIG. 26 views (a) and (b)): operation of opening and closingthe other clamp 2B by use of the first cam mechanism 71.(4) D-D (FIG. 27 views (a) and (b)): operation of opening and closingthe lid 10 by use of the fourth cam mechanism 74.(5) E-E (FIG. 28 views (a) and (b)): operation of opening and closingone heater 3A by use of the third cam mechanism 73.

In FIG. 28 views (a) and (b), a semidisc 91A and a photo sensor 91B thatare used to detect a rotational position of the camshaft 7 is providedin front of the third cam mechanism 73.

As shown in FIG. 24 views (a) and (b) to FIG. 28 views (a) and (b), itis understood that since each operation member is driven by each cammechanism that is provided on the camshaft 7, each of theopenable-and-closable side of the paired right and left clamps 2A and2B, one heater 3A, the lid 10, or the like is driven at a predeterminedtiming.

Other Modified Example

Hereinbelow, the other modified example of the embodiment will bedescribed.

In the embodiment, in the aforementioned configuration shown in FIG. 4or the like, constitution may be adopted which includes a positionlimiting member that is used to limit the forward movable range Z of(refer to FIG. 6) or the backward movable range K (refer to FIG. 6) ofat least one of the paired right and left clamps 2A and 2B and isconfigured by a forward movement stopper or a backward movement stopper.

This position limiting member limits, for example, the forward movablerange or the backward movable range of the fixed-side clamp.

This position limiting member has a function of adjusting a tension thatis applied to the optical fiber 11 to be in an adequate range.

Furthermore, a constitution may also be adopted which includes: thefifth cam mechanism (not shown in the figure) that is disposed on thecamshaft 7 on the same axis as those of the first to third cammechanisms 71 to 73 or is disposed on the other camshaft (not shown inthe figure) parallel to the camshaft 7 and is rotationally driven bycontrol of the motor 6; and a mechanism that controls the displacementof the fifth cam mechanism so as to cause the position limiting memberconfigured by the above-described forward movement stopper or thebackward movement stopper to move, wherein the same motor 6 drives theclamps 2A and 2B (including a mechanism operates to pull them), theheater 3, and the aforementioned position limiting member by use of thefirst to third cam mechanisms 71 to 73 and the fifth cam mechanism (notshown in the figure).

In the embodiment, a constitution may also be adopted which includes: asecond cam mechanism that is disposed on the camshaft 7 on the same axisas those of the first and third cam mechanisms 71 and 73 or is disposedon the other camshaft parallel to the camshaft 7; and a mechanism thatcontrols the displacement of the second cam mechanism so as to cause theposition limiting member configured by the above-described forwardmovement stopper or the backward movement stopper to move.

The second cam mechanism is rotationally driven by, for example, controlof the motor 6.

In the embodiment, a constitution may also be adopted in which the samemotor 6 controls movement of the clamps 2A and 2B and the heater 3 byuse of the first cam mechanism 71, the third cam mechanism 73, and thesecond cam mechanism and by the fifth and second force-applying member,and furthermore, the same motor controls movement of a tension mechanism(a mechanism applies a tension to an optical fiber) by use of the secondcam mechanism and by the above-mentioned position limiting member.

Additionally, in the aforementioned configuration, a constitution mayalso be adopted which further includes: the first force-applying member41 that is used to limit the forward movable range Z or the backwardmovable range K of at least one of the paired right and left clamps 2Aand 2B or a third force-applying member (not shown in the figure) thatapplies a tension in an opposite direction relative to the firstforce-applying member; the sixth cam mechanism (not shown in the figure)that is disposed on the camshaft 7 on the same axis as those of thefirst to third cam mechanisms 71 to 73 or is disposed on the othercamshaft (not shown in the figure) parallel to the camshaft 7 and isrotationally driven by control of the motor 6; and a mechanism (appliedforce controller) in which the displacement of the sixth cam mechanismcontrols the applied force of the first force-applying member 41 or thethird force-applying member to be stronger or to be weaker, wherein thesame motor 6 controls a mechanism (applied force controller) thatcontrols the clamps 2A and 2B (including a mechanism pulls them), theheater 3, and the first or third force-applying member 41 or 43 by useof the first to third cam mechanisms 71 to 73 and the sixth cammechanism (not shown in the figure).

Moreover, in the aforementioned configuration, a constitution may alsobe adopted which includes: the first force-applying member 41 or thethird force-applying member (not shown in the figure) which applies atension to the optical fiber 11; the above-mentioned second cammechanism (not shown in the figure); the above-described sixth cammechanism (not shown in the figure); a mechanism in which thedisplacement of the second cam mechanism controls a tensile of theoptical fiber 11 which is due to a pulling force of the firstforce-applying member 41; and an applied force controller that controlsthe displacement of the sixth cam mechanism to make the applied force ofthe first force-applying member or the third force-applying memberstronger or an applied force controller that controls them to make itweaker.

In this case, it is preferable that the same motor 6 control the clamps,the tension mechanism, the heaters, and the applied force controller byuse of the first to third cam mechanisms and the sixth cam mechanism.

The reinforcing heating device shown in FIG. 45 is different from thereinforcing heating device shown in FIGS. 6 to 11 in that the sixth cammechanism 76 is provided, the force-applying mechanism 41 (firstforce-applying member) and force-applying mechanism 43 (thirdforce-applying member) are provided, and a movable rear wall 131 isprovided.

The sixth cam mechanism 76 is formed in a disk-shape so as to beinclined with respect to the surface perpendicular to the camshaft 7.

The sixth cam mechanism 76 is inclined with respect to the surfaceperpendicular to the camshaft 7, for example, at an angle greater than0° and less than 90°.

The movable rear wall 131 is provided at the position opposed to therear surface of the clamp 2A (fixed-side) and is movable in thefront-back direction (horizontal direction in the drawing).

The movable rear wall 131 may be configured to be movable by the slidemechanism 21 or the like.

A recess 131 b into which a bottom 76 a of the sixth cam mechanism 76 isinserted is formed on the upper face 131 a of the movable rear wall 131.

For this reason, the movable rear wall 131 is located at the positiondepending on the position in the front-back direction (horizontaldirection in the drawing) of the bottom 76 a of the sixth cam mechanism76.

For example, in the case where the bottom 76 a of the sixth cammechanism 76 is close to the clamp 2A, the movable rear wall 131 alsocomes close to the clamp 2A (refer to FIG. 45). In the case where thebottom 76 a of the sixth cam mechanism 76 is far from the clamp 2A, themovable rear wall 131 is also located far from the clamp 2A at a largedistance (refer to FIG. 46).

The force-applying mechanism 43 (third force-applying member) includesforce-applying members 43 a and 43 b which are provided at the rear-edgeface of the fixed-side 2Aa of the clamp 2A and the front surface of themovable rear wall 131, respectively.

The force-applying members 43 a and 43 b are magnetic members such as apermanent magnet or an electromagnet and have the same magnetic pole aseach other.

In the drawing shown as an example, both the force-applying members 43 aand 43 b have a south polarity.

The force-applying mechanism 43 presses the clamp 2A by a repulsiveforce between the force-applying members 43 a and 43 b and adjusts atension to be applied to the optical fiber 11.

The force-applying mechanism 41 (first force-applying member) includesforce-applying members 41 a and 41 b which are provided at a front-edgeface of a fixed-side 2Aa of the clamp 2A and the heater attachment base31B, respectively.

The force-applying members 41 a and 41 b have the same magnetic pole aseach other.

Both the force-applying members 41 a and 41 b shown in the drawing as anexample have a north polarity.

In the state shown in FIG. 45, the clamps 2A and 2B and the heaters 3Aand 3B are opened by pressure of the first cam mechanism 71 and thethird cam mechanism 73, respectively.

Since the sixth cam mechanism 76 is inclined so as to have anorientation such that, as it approaches the movable rear wall 131, itapproaches the clamp 2A, the bottom 76 a is located near the clamp 2A.

Accordingly, the movable rear wall 131 is located adjacent to the clamp2A.

Since the movable rear wall 131 is close to the clamp 2A, a force in adirection of approaching the heater attachment base 31B (the rightdirection in the drawing) is applied to the clamp 2A due to a repulsiveforce between the force-applying members 43 a and 43 b.

Also, a force in a direction away from the heater attachment base 31B(the left direction in the drawing) is applied to the clamp 2A due to arepulsive force between the force-applying members 41 a and 41 b.

As shown in FIG. 46, the first cam mechanism 71 is displaced inaccordance with the rotation of the camshaft 7, theopenable-and-closable side 2Ab of the clamp 2A moves in a direction ofapproaching the fixed-side 2Aa, and the openable-and-closable side 2Aband the fixed-side 2Aa thereby grasps the optical fiber 11.

Furthermore, the heater attachment base 31A comes close to the heaterattachment base 31B in accordance with the displacement of the third cammechanism 73, the sleeve 12 is sandwiched between the heaters 3A and 3B,and the sleeve 12 is heat-shrunk.

At this time, since the sixth cam mechanism 76 is inclined so as to havean orientation such that, as it approaches the movable rear wall 131, itis farther from the clamp 2A, the movable rear wall 131 moves to theposition far from the clamp 2A at a large distance.

Consequently, the repulsive force between the force-applying members 43a and 43 b becomes weaker; however, the repulsive force between theforce-applying members 41 a and 41 b does not significantly change, andtherefore, a tension that is applied to the optical fiber 11 increasesby the clamp 2A.

As shown in FIG. 45, when the camshaft 7 further rotates, the heaterattachment base 31A moves in a direction away from the heater attachmentbase 31B by the third cam mechanism 73, the sleeve 12 is released, theopenable-and-closable side 2Ab of the clamp 2A moves in a direction awayfrom the fixed-side 2Aa by the first cam mechanism 71, and the graspingof the optical fiber 11 is released.

The first force-applying member 41 may have a function of limiting, forexample, the forward movable range Z or the backward movable range K theclamp of the fixed-side (or openable-and-closable side) of at least oneof the paired right and left clamps 2A and 2B.

The second cam mechanism may be disposed on, for example, the camshaft 7on the same axis as those of the first and third cam mechanisms 71 and73 or is disposed on the other camshaft (not shown in the figure)parallel to the camshaft 7.

The second cam mechanism may have a structure that is rotationallydriven by control of the motor 6.

In the embodiment, a constitution may also be adopted in which the samemotor 6 controls movement of the clamps 2A and 2B and the heater 3 byuse of the first and third cam mechanisms 71 and 73, and the second cammechanism and by the fifth and second force-applying member, andfurthermore, the same motor controls movement of a tension mechanism (amechanism applies a tension to an optical fiber) by use of the secondcam mechanism and by the first force-applying member or the thirdforce-applying member.

As described above, as a result of adopting the configuration that canmove each force-applying member for adjusting a tension to be applied tothe optical fiber 11, it is possible to properly adjust the tension witha downsized configuration.

Moreover, in the aforementioned configuration, a constitution may alsobe adopted which further limits a forward movable range or a backwardmovable range of at least one of the paired right and left clamps.

Even in the case of adopting the above-described any configurations, aneffect that it is possible to reduce the entire reinforcing heatingdevice in size is conspicuously obtained.

(Action and Effect)

According to the optical-fiber-spliced portion reinforcing heatingdevice of the second embodiment according to the invention in the abovedescription, since a constitution is provided which utilizes the motor 6that is the same drive source and drives the paired right and leftclamps 2A and 2B, one heater 3A, the lid 10, or the like by each cammechanism that is provided on the same axis, it is possible to reducethe entire reinforcing heating device in size.

Moreover, similar to the aforementioned first embodiment, when thesleeve 12 is sandwiched between two heaters 3A and 3B and is heatshrunk, breaking of the optical fiber 11 or degradation in long-termreliability thereof is prevented by releasing an excessive tension thatis to be applied to the optical fiber 11, and a device is prevented frombeing larger in size.

Consequently, it is possible to heat-shrink the sleeve 12 in a shorteramount of time with a high level of reliability, and anoptical-fiber-spliced portion reinforcing heating device 1 having a highlevel of handleability can be realized.

In addition, the technical scope of the invention is not limited to theabove embodiments, and various modifications may be made withoutdeparting from the scope of the invention.

For example, in the aforementioned embodiments, the fifth force-applyingmember 45 is used in both the paired clamps 2A and 2B; however, thefifth force-applying member 45 may be used in only one of the clamps 2Aand 2B (that is, one side).

Additionally, in the above-mentioned embodiments, two heaters 3 (3A, 3B)are used; however, the number of heaters may be three or more.

What is claimed is:
 1. An optical-fiber-spliced portion reinforcingheating device comprising: a pair of clamps that respectively grasp oneportion and the other portion of a coated portion of an optical fiber,the optical fiber including a fusion-spliced portion, the fusion-splicedportion being coated with a sleeve, the coated portion being exposedfrom the sleeve; at least two or more heaters that are arranged to faceeach other so as to sandwich the sleeve; a first force-applying memberthat presses at least one of the paired clamps so as to apply a tensionto the optical fiber; and a second force-applying member that applies apressing force to at least one or more of the heaters via the sleeve byuse of one of an elastic member and a magnetic member in accordance withcontrol of a drive source, the heaters being arranged to face each otherwith the sleeve interposed therebetween, wherein a pressing force thatis to be applied to the sleeve by the second force-applying member isset to be greater than a tension that is to be applied to the opticalfiber by the first force-applying member, before the optical fiber isgrasped, in a state in which one of the clamps is separated from heatersby the first force-applying member and in a state in which the pairedclamps grasp the optical fiber and a tension is not applied to theoptical fiber, the heaters press the sleeve by a pressing force by thesecond force-applying member, as a result of moving the optical fiber ina pressing direction which is due to movement of the sleeve ordeformation of the sleeve after starting of the press, one of the clampsis drawn to a forward movement direction by a tension due to movement ofthe optical fiber, one of the clamps is configured so as to be stoppedat a position away from an end of a movable range, therefore, in a statein which a tension is applied to the optical fiber, in one of theclamps, a backward movable range in a direction away from the heaters inthe longitudinal direction of the optical fiber is ensured and a forwardmovable range that allows movement to the heater side is ensured, andone of the clamps is thereby configured to move in a direction in whicha tension that is applied to the optical fiber as a result of pressingthe sleeve by the heaters and by the second force-applying member isdiminished.
 2. The optical-fiber-spliced portion reinforcing heatingdevice according to claim 1, wherein both the paired clamps are movableback and forth in the longitudinal direction of the optical fiber. 3.The optical-fiber-spliced portion reinforcing heating device accordingto claim 1, wherein one of the heaters that are arranged so as to faceeach other with the sleeve interposed therebetween is movable and theother thereof is fixed.
 4. The optical-fiber-spliced portion reinforcingheating device according to claim 1, wherein a pressing force that is tobe applied to the sleeve by the heaters exceeds the tension of thefusion-spliced portion of the optical fiber under a rupture evaluationtest.
 5. The optical-fiber-spliced portion reinforcing heating deviceaccording to claim 1, wherein pressing faces of the heaters which faceeach other with the sleeve interposed therebetween are arranged in asubstantially vertical direction, a tensile strength member isconsistently arranged in a substantially downward direction by utilizinga weight of the tensile strength member that is inserted into the insideof the sleeve, and the direction of the sleeve is thereby constant. 6.The optical-fiber-spliced portion reinforcing heating device accordingto claim 1, wherein after heating of the sleeve is completed, theheaters are immediately separated from the sleeve, heat-transfer to thesleeve is interrupted, and the sleeve is thereby rapidly cooled byintroduction of external air into the periphery of the sleeve.